Adhesive layer-equipped transparent surface material, display device and processes for their production

ABSTRACT

Provided is an adhesive layer-equipped transparent surface material that can easily be bonded to another surface material (a display panel, etc.) and that, when bonded to another surface material, is less likely to have voids left at the interface between the adhesive layer and another surface material. An adhesive layer-equipped transparent surface material  1  comprises an adhesive layer  14  formed on at least one surface of a protective plate  10  (a transparent surface material), wherein the adhesive layer  14  has a layer portion  18  spreading over the surface of the protective plate  10  and a barrier portion  20  surrounding the periphery of the layer portion  18;  and the layer portion  18  has a shear modulus at 35° C. of from 0.5 to 100 kPa.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 15/449,190, filed Mar. 3, 2017, which is in turn acontinuation application of U.S. patent application Ser. No. 13/914,273,filed Jun. 10, 2013, which is in turn a continuation application ofInternational Application No. PCT/JP2011/078352, filed Dec. 7, 2011,which claims priority to Japanese Patent Application No 2010-273720,filed Dec. 8, 2010. The contents of these applications are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an adhesive layer-equipped transparentsurface material, a display device having a display panel protected bythe transparent surface material, and processes for their production.

BACKGROUND ART

As a display device having a display panel protected by a transparentsurface material (a protective plate), the following one is known. Forexample, a display device is known wherein a display panel and aprotective plate are bonded via an adhesive sheet (Patent Documents 1and 2).

Bonding of the display panel and the protective plate may be carried outby the following method so that voids will not remain at the interfacebetween the adhesive sheet and the display panel or the protectiveplate.

For example, the bonding may be carried out by a method wherein thedisplay panel and the protective plate are bonded via an adhesive sheetin a reduced pressure atmosphere, and then the atmosphere is returned tothe atmospheric pressure atmosphere.

According to such a method, as shown in FIG. 9, even if an independentvoid 110 remains at the interface between an adhesive sheet 100 and adisplay panel 50 or a protective plate 10 at the time when the displaypanel 50 and the protective plate 10 are bonded via the adhesive sheet100 in a reduced pressure atmosphere, if the atmosphere is then returnedto the atmospheric pressure atmosphere, the volume of the void 110decreases, and the void 110 will eventually disappear, due todifferential pressure between the pressure in the void 110 (the reducedpressure) and the pressure exerted to the adhesive sheet 100 (theatmospheric pressure).

However, as shown in FIG. 10, a void 120 open to exterior is likely tobe formed along the periphery of the adhesive sheet 100 in many cases,when the display panel 50 and the protective plate 10 are bonded via theadhesive sheet 100. When the assembly having the display panel 50 andthe protective plate 10 bonded via the adhesive sheet 100 in a reducedpressure atmosphere, is returned to the atmospheric pressure atmosphere,the pressure in the void 120 open to exterior is also returned to theatmospheric pressure, whereby the volume of the void 120 will notdecrease, and the void 120 will remain.

Further, in such a method, after bonding the adhesive sheet to one ofsurface materials i.e. the display panel and the protective plate, it isnecessary to bond the remaining surface material to the adhesive sheet.That is, the bonding step is required to be carried out twice, wherebythe bonding of the display panel and the protective plate becomescumbersome.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP-A-2006-290960

Patent Document 2: JP-A-2009-263502

DISCLOSURE OF INVENTION Technical Problem

The present invention is to provide an adhesive layer-equippedtransparent surface material that can easily be bonded to anothersurface material (such as a display panel) and that, when bonded toanother surface material, is less likely to have voids left at theinterface between the adhesive layer and another surface material; aprocess for producing an adhesive layer-equipped transparent surfacematerial that has formation of voids sufficiently prevented at theinterface between the adhesive layer and the transparent surfacematerial, and that can be simply bonded to another surface material andthat, when bonded to another surface material, is less likely to havevoids left at the interface between the adhesive layer and anothersurface material; a display device that has formation of voidssufficiently prevented at the interface between the adhesive layer andthe display panel; and a process for producing a display device, wherebya display panel and a transparent surface material (a protective plate)can easily be bonded, and voids are less likely to remain at theinterface between the adhesive layer and the display panel.

Solution to Problem

The adhesive layer-equipped transparent surface material of the presentinvention is an adhesive layer-equipped transparent surface materialcomprising a transparent surface material and an adhesive layer formedon at least one surface of the transparent surface material, wherein theadhesive layer has a layer portion spreading over the surface of thetransparent surface material and a barrier portion surrounding theperiphery of the layer portion; and the layer portion has a shearmodulus at 35° C. of from 0.5 to 100 kPa.

It is preferred that the layer portion is made of a cured product of alayer portion-forming curable resin composition comprising the followingcurable compound (II) and the following non-curable oligomer (D):

Curable compound (II): at least one curable compound which undergoes acuring reaction at the time of curing the curable resin composition,provided that at least one of said at least one curable compound has ahydroxy group which is not reactive at the time of curing the curableresin composition;

Non-curable oligomer (D): an oligomer which does not undergo a curingreaction with the curable compound (II) at the time of curing thecurable composition and which has a hydroxy group.

It is preferred that the curable compound (II) contains a monomer whichhas a curable group and a hydroxy group.

It is preferred that the curable compound (II) contains an oligomer (A′)which has a curable group and has a number average molecular weight offrom 1,000 to 100,000, and a monomer (B′) which has a curable group andhas a molecular weight of from 125 to 600; and the monomer (B′) containsa monomer (B3) having a hydroxy group.

It is preferred that the non-curable oligomer (D) is a polyoxyalkylenepolyol, and the oligomer (A′) is a urethane oligomer synthesized byusing a polyoxyalkylene polyol and a polyisocyanate as raw materials.

It is preferred that the oligomer (A′) has an acryl group, and at leasta part of the monomer (B′) has a methacryl group.

It is preferred that the monomer (B3) contains a hydroxy methacrylatewhich has a C₃₋₈ hydroxyalkyl group having from 1 to 2 hydroxy groups.

It is preferred that the monomer (B′) contains a monomer (B4) selectedfrom an alkyl methacrylate having a C₈₋₂₂ alkyl group.

It is preferred that the layer portion-forming curable resin compositiondoes not contain a chain transfer agent, or contains a chain transferagent in an amount of at most 1 part by mass per 100 parts by mass ofthe curable compound (II).

It is preferred that the layer portion-forming curable resin compositioncontains a photo-polymerization initiator (C2), and the curable compound(II) is a photo-curable compound.

It is preferred that the transparent surface material is a protectiveplate for a display device.

It is preferred that the adhesive layer-equipped transparent surfacematerial further has a removable protective film covering the surface ofthe adhesive layer.

The process for producing the adhesive layer-equipped transparentsurface material of the present invention comprises the following steps(a) to (e):

(a) a step of applying a liquid barrier portion-forming curablecomposition to a peripheral portion of the surface of the transparentsurface material to form an uncured barrier portion,

(b) a step of supplying a layer portion-forming curable resincomposition to a region surrounded by the uncured barrier portion,

(c) a step of overlaying, in a reduced pressure atmosphere of at most100 Pa, a protective film-bonded supporting surface material on thelayer portion-forming curable resin composition so that the protectivefilm is in contact with the layer portion-forming curable resincomposition, to obtain a laminate wherein an uncured layer portion madeof the layer portion-forming curable resin composition, is sealed by thetransparent surface material, the protective film and the uncuredbarrier portion,

(d) a step of curing the uncured layer portion and the uncured barrierportion in a state where the laminate is held in an elevated pressureatmosphere of at least 50 kPa, to form an adhesive layer having a layerportion and a barrier portion, and

(e) a step of removing the supporting surface material from theprotective film.

The display device of the present invention comprises a display paneland the adhesive layer-equipped transparent surface material of thepresent invention bonded to the display panel so that the adhesive layeris in contact with the display panel.

It is preferred that the display panel is a liquid crystal display panelof in-plane switching system.

The process for producing the display device of the present inventioncomprises laminating and bonding, in a reduced pressure atmosphere of atmost 100 Pa, the display panel and the adhesive layer-equippedtransparent surface material so that the adhesive layer is in contactwith the display panel.

Advantageous Effects of Invention

The adhesive layer-equipped transparent surface material of the presentinvention can easily be bonded to another surface material (such as adisplay panel) and when bonded to another surface material, is lesslikely to have voids left at the interface between the adhesive layerand another surface material.

According to the process for producing an adhesive layer-equippedtransparent surface material of the present invention, it is possible toproduce an adhesive layer-equipped transparent surface material that hasformation of voids sufficiently prevented at the interface between theadhesive layer and the transparent surface material, and that can easilybe bonded to another surface material and that, when bonded to anothersurface material, is less likely to have voids left at the interfacebetween the adhesive layer and another surface material.

The display device of the present invention will be one having formationof voids sufficiently prevented at the interface between the adhesivelayer and the display panel.

According to the process for producing a display device of the presentinvention, bonding of a display panel and a transparent surface material(a protective plate) is simple, and voids are less likely to remain atthe interface between the adhesive layer and the display panel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view illustrating an example of the adhesivelayer-equipped transparent surface material of the present invention.

FIG. 2 is a plan view illustrating an example of the mode in step (a).

FIG. 3 is a cross-sectional view illustrating an example of the mode instep (a).

FIG. 4 is a plan view illustrating an example of the mode in step (b).

FIG. 5 is a cross-sectional view illustrating an example of the mode instep (b).

FIG. 6 is a cross-sectional view illustrating an example of the mode instep (c).

FIG. 7 is a cross-sectional view illustrating an example of the displaydevice of the present invention.

FIG. 8 is a perspective view illustrating the mode of a void at theinterface between an adhesive layer and a display panel at the time ofbonding the display panel and the adhesive layer-equipped transparentsurface material of the present invention.

FIG. 9 is a perspective view illustrating the mode of a void at theinterface between an adhesive sheet and a display panel at the time whena protective plate and the display panel are bonded via the adhesivesheet.

FIG. 10 is a perspective view illustrating the mode of a void at theinterface between an adhesive sheet and a display panel at the time whena protective plate and the display panel are bonded via the adhesivesheet.

DESCRIPTION OF EMBODIMENTS

In this specification, “transparent” means to have optical transparency,and “(meth)acrylate” means an acrylate or a methacrylate.

<Adhesive Layer-equipped Transparent Surface Material>

FIG. 1 is a cross-sectional view illustrating an example of the adhesivelayer-equipped transparent surface material of the present invention.

The adhesive layer-equipped transparent surface material 1 comprises aprotective plate 10 (a transparent surface material), a light-shieldingprinted portion 12 formed at the peripheral portion of the surface ofthe protective plate 10, an adhesive layer 14 formed on the surface ofthe protective plate 10 on the side where the light-shielding printedportion 12 is formed, and a removable protective film 16 covering thesurface of the adhesive layer 14.

Protective Plate

The protective plate 10 is one which is provided on the image displayside of the after-described display panel to protect the display panel.

The protective plate 10 may, for example, be a glass plate or atransparent resin plate, and a glass plate is most preferred not onlyfrom such a viewpoint that the transparency is high to an emission lightor reflection light from a display panel but also from such a viewpointthat it has light resistance, low birefringence, high planarity,surface-scratching resistance and high mechanical strength. A glassplate is preferred also from such a viewpoint that it permits light tosufficiently pass therethrough to cure a photocurable resin composition.

As a material for the glass plate, a glass material such as soda limeglass may be mentioned, and less bluish highly transparent glass havinga lower iron content (white plate glass) is more preferred. In order toincrease the safety, tempered glass may be used as the surface material.Especially when a thin glass plate is to be used, it is preferred toemploy a chemically tempered glass plate.

As a material of the transparent resin plate, a resin material having ahigh transparency (such as a polycarbonate or a polymethyl methacrylate)may be mentioned.

To the protective plate 10, surface treatment may be applied in order toimprove the interfacial adhesion to the adhesive layer 14. The methodfor such surface treatment may, for example, be a method of treating thesurface of the protective plate 10 with a silane coupling agent, or amethod of forming a thin film of silicon oxide by an oxidation flame bymeans of a flame burner.

To the protective plate 10, an antireflection layer may be provided onthe surface opposite to the side having the adhesive layer 14 formed, inorder to increase the contrast of a display image. The antireflectionlayer may be provided by a method of directly forming an inorganic thinfilm on the surface of the protective plate 10 or a method of bonding atransparent resin film provided with an antireflection layer, to theprotective plate 10.

Further, depending upon the particular purpose, a part or whole of theprotective plate 10 may be colored, a part or whole of the surface ofthe protective plate 10 may be made to have a frosted glass state toscatter light, or a part or whole of the surface of the protective plate10 may have fine irregularities, etc. formed to refract or reflecttransmitted light. Otherwise, a colored film, a light scattering film, aphotorefractive film, a light reflecting film, etc. may be bonded on apart or whole of the surface of the protective plate 10.

The shape of the protective plate 10 is usually rectangular.

Since the process of the present invention is particularly suitable forthe production of an adhesive layer-equipped transparent surfacematerial 1 having a relatively large area, the size of the protectiveplate 10 is preferably at least 0.5 m×0.4 m, particularly preferably atleast 0.7 m×0.4 m, in the case of television receivers. The upper limitfor the size of the protective plate 10 is determined by the size of thedisplay panel in many cases. Further, a display device with a size beingtoo large tends to be difficult to handle in installation, etc. Fromsuch restrictions, the upper limit for the size of the protective plate10 is usually about 2.5 m×1.5 m.

The thickness of the protective plate 10 is usually from 0.5 to 25 mm inthe case of a glass plate from the viewpoint of mechanical strength andtransparency. In applications for television receivers, PC displays,etc. to be used indoors, the thickness is preferably from 1 to 6 mm witha view to reducing the weight of a display device, and in applicationsfor public displays to be installed outdoors, it is preferably from 3 to20 mm. In a case where chemically tempered glass is to be used, thethickness of the glass is preferably from about 0.5 to 1.5 mm from theviewpoint of the strength. In the case of a transparent resin plate, thethickness is preferably from 2 to 10 mm.

Light-Shielding Printed Portion

The light-shielding printed portion 12 is one to shield wiring members,etc. connected to a display panel, so that other than the image displayregion of the after-described display panel is not visible from theprotective plate 10 side. The light-shielding printed portion 12 may beformed on the surface of the side having the adhesive layer 14 formed oron the opposite side surface, and with a view to reducing a parallaxbetween the light-shielding printed portion 12 and the image displayregion, it is preferably formed on the surface of the side where theadhesive layer 14 is to be formed. In a case where the protective plate10 is a glass plate, it is preferred to use a ceramic printing so thatthe light-shielding printed portion 12 contains a black pigment, wherebythe light shielding property becomes high. In a case where thelight-shielding printed portion is to be formed on the side opposite tothe side having the adhesive layer formed, a transparent film having thelight-shielding printed portion preliminarily provided, may be bonded tothe protective plate. A film having a light shielding printed portionprovided along the peripheral portion of a transparent film on the sideto be bonded to the protective plate and an antireflection layerprovided on its rear side i.e. the outermost surface of a displaydevice, may be bonded to the protective plate.

Adhesive Layer

The adhesive layer 14 has a layer portion 18 spreading over the surfaceof the protective plate 10 and a barrier portion 20 surrounding theperiphery of the layer portion 18 in contact therewith.

Layer Portion

The layer portion 18 is a layer made of a transparent resin formed bycuring a liquid layer portion-forming curable resin composition(hereinafter sometimes referred to also as the first composition).

The shear modulus at 35° C. of the layer portion 18 is from 0.5 to 100kPa, and the lower limit value is preferably 0.8 kPa. The upper limitvalue is preferably 25 kPa, more preferably 12 kPa. When the shearmodulus is at least 0.5 kPa, the shape of the layer portion 18 can bemaintained. Further, even in a case where the thickness of the layerportion 18 is relatively thick, the thickness over the entire layerportion 18 can be uniformly maintained, and at the time of bonding anadhesive layer-equipped transparent surface material 1 and a displaypanel, voids are less likely to be formed at the interface between thedisplay panel and the adhesive layer 14. When the shear modulus is atmost 100 kPa, at the time of bonding a display panel and an adhesivelayer-equipped transparent surface material 1 in a reduced pressureatmosphere and then returning the atmosphere to an atmospheric pressureatmosphere, voids formed at the interface between the adhesive layer 14and the display panel will disappear in a short time and are less likelyto remain. This is considered to be such that since the molecularmobility of the resin material constituting the layer portion 18 isrelatively high, when the display panel and the adhesive layer-equippedtransparent surface material 1 are bonded in a reduced pressureatmosphere and then returned to an atmospheric pressure atmosphere, thevolume of voids 110 tends to readily decrease due to the differentialpressure between the pressure in the voids (reduced pressure) and thepressure exerted to the layer portion 18 (atmospheric pressure).

To determine the shear modulus at 35° C. of the layer portion 18, usinga rheometer (modular rheometer Physica MCR-301, manufactured by AntonPaar), a space between a measuring spindle and a light-transmittingplate is adjusted to be the same as the thickness of the layer portion18, and the uncured first composition is disposed in the space, andwhile applying heat or light required for curing to the firstcomposition, the shear modulus during the curing process is measured,and the measured value under the curing conditions at the time offorming the layer portion 18 is taken as the shear modulus of the layerportion 18.

Barrier Portion

The barrier portion 20 is a portion made of a transparent resin formedby applying and curing a liquid barrier portion-forming curable resincomposition (hereinafter sometimes referred to also as the secondcomposition). As the region outside of the image display region of adisplay panel is relatively narrow, the width of the barrier portion 20is preferably made narrow. The width of the barrier portion 20 ispreferably from 0.5 to 2 mm, more preferably from 0.8 to 1.6 mm.

The thickness of the layer portion 18 is preferably from 0.03 to 2 mm,more preferably from 0.1 to 0.8 mm. When the thickness of the layerportion 18 is at least 0.03 mm, the layer portion 18 is capable ofeffectively damping an impact, etc. by external force from theprotective plate 10 side, thereby to protect the display panel. Further,in the process for producing a display device of the present invention,even if a foreign matter not exceeding the thickness of the layerportion 18 is included between the display panel and the adhesivelayer-equipped transparent surface material 1, the thickness of thelayer portion 18 will not be substantially changed, and an influenceover the optical transparency is little. When the thickness of the layerportion 18 is at most 2 mm, voids are less likely to remain in the layerportion 18, and the entire thickness of the display device will not beunnecessarily thick.

The thickness of the barrier portion 20 is preferably slightly more thanthe thickness of the layer portion 18 (the difference being at most 20μm), but the thickness is not limited thereto.

That is, when the thickness of the barrier portion 20 is more than thethickness of the layer portion 18, at the time of bonding the displaypanel 50 and the adhesive layer-equipped transparent surface material 1as shown in FIG. 8, even if a void 110 remains at the interface betweenthe display panel 50 and the adhesive layer 14 at the peripheral portionof the adhesive layer 14, the void 110 is shielded by the barrierportion 20, whereby the void 110 is not open to exterior and becomes anindependent void 110. Accordingly, when, after bonding the display panel50 and the adhesive layer-equipped transparent surface material 1 in areduced pressure atmosphere, the pressure is returned to the atmosphericpressure atmosphere, the volume of the void 110 will decrease, and thevoid 110 will eventually disappear, by the differential pressure betweenthe pressure in the void 110 (the reduced pressure) and the pressureexerted to the adhesive layer 14 (the atmospheric pressure).

The thicknesses of the layer portion 18 and the barrier portion 20 canbe adjusted by the amounts of the liquid first composition and secondcomposition to be supplied to the surface of the protective plate 10 andthe respective shrinkages at the time of their curing.

The polymerization shrinkage of the first composition (the layerportion-forming curable resin composition) to be used in the presentinvention becomes low as the content of the non-curable oligomerincreases. Accordingly, the polymerization shrinkage of the secondcomposition becomes relatively high, and there may be a case where thethickness of the barrier portion 20 becomes less than the thickness ofthe layer portion 18.

In a case where a void open to exterior is formed at the interfacebetween the adhesive layer and another surface material due to such asituation that the thickness of the barrier portion 20 is equal to thelayer portion 18 or less than the layer portion 18, a method forovercoming such a drawback may, for example, be a method wherein at thetime of curing the layer portion 18 and the barrier portion 20, asupporting surface material 36 having a difference in level provided onthe lower surface is mounted in order to make the upper surface of thelayer portion 18 after the curing to be lower than the upper surface ofthe barrier portion 20, or a method wherein at the time of forming thesecond composition into a barrier-form, the second composition issupplied to the surface of the protective plate 10 so that it becomeslarger than the thickness after curing, and further, before supplyingthe first composition, light to cure the second composition is appliedfor a short time to partially cure or thicken the second composition tosecure the thickness of the barrier portion. In a case where prior tosupplying the first composition, the second composition is partiallycured, it is preferred to form the line width of the barrier portion 20to be fine, so that the barrier portion can easily be deformed at thetime of lamination with the after-described supporting surface material.

Supporting Surface Material

The supporting surface material 36 shown in FIG. 6, to be used in theafter-described process of the present invention, is a transparentsurface material such as a glass plate or a resin plate. In a case wherea supporting surface material 36 having a relatively large area is to beused, if the supporting surface material 36 has warpage or defection,the surface state of the adhesive layer 14 may be adversely affected,and therefore, it is preferred to employ a glass plate having higherrigidity. Further, in a case where a glass plate is employed as thesupporting surface material 36, the thickness of the glass plate ispreferably from 0.5 to 10 mm. If the thickness is less than 0.5 mm,warpage or deflection is likely to occur, and if it is thicker than 10mm, the mass of the supporting surface material 36 becomes unnecessarilylarge, and the supporting surface material 36 is likely to be displacedat the time of moving the laminate before curing the adhesive layer 14.The thickness is particularly preferably from 1.0 to 5.0 mm.

Protective Film

The protective film 16 is required to be not firmly bonded to theadhesive layer 14 and to be able to be bonded to the supporting surfacematerial 36 in the after-described process of the present invention.Therefore, the protective film 16 is preferably a self-adhesiveprotective film such that one surface of a substrate film having arelatively low adhesion such as a polyethylene, a polypropylene or afluorinated resin, is made to be an adhesive surface.

The adhesive force of the adhesive surface of the protective film 16 ispreferably from 0.01 to 0.1 N, more preferably from 0.02 to 0.06 N, by atest specimen with a width of 50 mm in a 180° C. peeling test at apeeling rate of 300 mm/min against an acrylic plate. When the adhesiveforce is at least 0.01 N, bonding to the supporting surface material 36is possible, and when it is at most 0.1 N, it is easy to peel theprotective film 16 from the supporting surface material 36.

A preferred thickness of the protective film 16 may vary depending uponthe resin to be used, but in a case where a relatively flexible film ofe.g. polyethylene or polypropylene is to be used, the thickness ispreferably from 0.04 to 0.2 mm, more preferably from 0.06 to 0.1 mm.When it is at least 0.04 mm, it is possible to prevent deformation ofthe protective film 16 at the time of peeling the protective film 16from the adhesive layer 14, and when the thickness is at most 0.2 mm,the protective film 16 is likely to be deflected at the time of peeling,and can easily be peeled.

Further, it is also possible to further facilitate peeling from theadhesive layer 14 by providing a rear surface layer on the back surfaceopposite to the adhesive surface of the protective film 16. Also forsuch a rear surface layer, it is preferred to employ a film havingrelatively low adhesion made of e.g. a polyethylene, a polypropylene ora fluorinated resin. In order to further facilitate the peeling, it isalso possible to apply a release agent such as silicone to the adhesivelayer 14 within a range not to present an adverse effect.

Bonding of the protective film 16 to the supporting surface material 36is carried out by bonding the protective film 16 which is supplied as arolled material to the supporting surface material 36 by means of e.g. arubber roll. At that time, in order to avoid formation of voids betweenthe supporting surface material 36 and the adhesive surface of theprotective film 16, the rubber roll may be pressed against thesupporting surface material 36, or the bonding is carried out in areduced pressure atmosphere. It is preferred to employ a protective film16 slightly larger than the supporting surface material 36, so that theends of the protective film 16 can easily be gripped at the time ofpeeling from the adhesive layer 14.

Other Embodiments

The illustrated adhesive layer-equipped transparent surface material 1is an example wherein the transparent surface material is a protectiveplate for a display device. However, the adhesive layer-equippedtransparent surface material of the present invention is not limited tothe illustrated one and may be any material so long as the specificadhesive layer is formed on at least one surface of the transparentsurface material.

For example, the adhesive layer-equipped transparent surface material ofthe present invention may be one wherein the specific adhesive layer isformed on both surfaces of the transparent surface material.

Further, it may be one wherein a polarizing means (such as a film-formabsorption-type polarizer or a wire grid-type polarizer) or an opticalmodulator means (such as a phase difference film such as a ¼ retardationsheet, or a stripe-patterned phase difference film) is provided betweenthe transparent surface material (the protective plate) and the specificadhesive layer.

<Process for Producing Adhesive Layer-Equipped Transparent SurfaceMaterial>

The process for producing the adhesive layer-equipped transparentsurface material of the present invention is a process comprising thefollowing steps (a) to (e):

(a) a step of applying a liquid barrier portion-forming curablecomposition to a peripheral portion of the surface of the transparentsurface material to form an uncured barrier portion,

(b) a step of supplying a layer portion-forming curable resincomposition to a region surrounded by the uncured barrier portion,

(c) a step of overlaying, in a reduced pressure atmosphere of at most100 Pa, a protective film-bonded supporting surface material on thelayer portion-forming curable resin composition so that the protectivefilm is in contact with the layer portion-forming curable resincomposition, to obtain a laminate wherein an uncured layer portion madeof the layer portion-forming curable resin composition, is sealed by thetransparent surface material, the protective film and the uncuredbarrier portion,

(d) a step of curing the uncured layer portion and the uncured barrierportion in a state where the laminate is held in an elevated pressureatmosphere of at least 50 kPa, to form an adhesive layer having a layerportion and a barrier portion, and

(e) a step of removing the supporting surface material from theprotective film.

The process of the present invention is a process wherein in a reducedpressure atmosphere, the liquid first composition is sealed in betweenthe transparent surface material and the protective film bonded to thesupporting surface material, and in a high pressure atmosphere such asan atmospheric pressure atmosphere, the sealed first composition iscured to form a layer portion. Sealing of the first composition underreduced pressure is not a method of injecting the layer portion-formingcurable resin into a shallow wide space between the transparent surfacematerial and the protective film bonded to the supporting surfacematerial, but a method of supplying the first composition substantiallyover the entire surface of the transparent surface material, and then,the protective film bonded to the supporting surface material isoverlaid to seal in the first composition between the transparentsurface material and the protective film bonded to the supportingsurface material.

An example of the method for producing a transparent laminate by sealinga liquid curable resin composition under reduced pressure and curing thecurable resin composition in an atmospheric pressure atmosphere, isknown. For example, WO2008/81838 and WO2009/16943 disclose a process forproducing such a transparent laminate and a curable resin composition tobe used in such a process, which are incorporated in this specificationby reference.

Step (a)

Firstly, a liquid second composition is applied to the peripheralportion of the surface of the transparent surface material to form anuncured barrier portion. The application is carried out by means of e.g.a printing machine or a dispenser.

The barrier portion prior to being cured in step (d), may have aninterfacial adhesion of at least a level whereby the liquid firstcomposition will not leak out from the interface between the uncuredbarrier portion and the transparent surface material and at theinterface between the uncured barrier portion and the protective film,and may have a hardness of a level whereby the shape can be maintained.For example, it is preferred that the barrier portion is formed by usinga second composition having a high viscosity.

Otherwise, the same composition as the first composition to be used forforming the layer portion may be applied to the peripheral portion ofthe surface of the transparent surface material and semi-cured, and sucha semi-cured composition may be used as the barrier portion prior tobeing cured in step (d).

The viscosity of the second composition is preferably from 500 to 3,000Pa·s, more preferably from 800 to 2,500 Pa·s, further preferably from1,000 to 2,000 Pa·s. When the viscosity is at least 500 Pa·s, the shapeof the uncured barrier portion can be maintained for a relatively longperiod of time, and the height of the uncured barrier portion can besufficiently maintained. When the viscosity is at most 3,000 Pa·s, theuncured barrier portion can be formed by coating.

The viscosity of the second composition is measured at 25° C. by meansof an E-model viscometer.

Further, in order to maintain the distance between the transparentsurface material and the display panel, spacer particles having apredetermined particle diameter may be incorporated to the secondcomposition.

It is preferred that after application of the liquid second composition,light to cure the second composition is applied for a short time topartially cure or thicken the second composition, whereby the shape ofthe barrier portion may better be maintained.

The second composition may be a photo-curable resin composition or aheat curable resin composition. As the second composition, aphotocurable resin composition comprising a curable compound and aphotopolymerization initiator (C) is preferred since the curing can becarried out at a low temperature, and the curing speed is high. Further,a high temperature is not required for the curing, and therefore, thedisplay panel is less likely to be damaged by a high temperature.

Otherwise, the same composition as the first composition to be used forforming the layer portion may be applied along the peripheral portion ofthe surface of the transparent surface material and semi-cured, and sucha semi-cured composition may be used as the barrier portion prior tobeing cured in step (d).

A barrier portion-forming photocurable resin composition which ispreferred as the second composition in the present invention, will bedescribed.

Barrier Portion-Forming Photocurable Resin Composition

The barrier portion-forming photocurable resin composition is a liquidcomposition comprising a photocurable compound (I) and aphotopolymerization initiator (C1).

Curable Compound (I)

The curable compound (I) preferably comprises at least one oligomer (A)having a curable group and having a number average molecular weight of30,000 to 100,000 and at least one monomer (B) having a curable groupand having a molecular weight of from 125 to 600.

The curable group in the oligomer (A) or the monomer (B) may, forexample, be an addition-polymerizable unsaturated group (such as anacryloyloxy group or a methacryloyloxy group), or a combination of anunsaturated group and a thiol group, and it is preferably a groupselected from an acryloyloxy group and a methacryloyloxy group in thatthe curing speed is high and a barrier layer having high transparencycan be obtained.

The curable group in the oligomer (A) and the curable group in themonomer (B) may be the same or different from each other. The curablegroup in the oligomer (A) having a relatively high molecular weighttends to have a lower reactivity than the curable group in the monomer(B) having a relatively low molecular weight, and accordingly, curing ofthe monomer (B) is likely to advance, whereby the viscosity of theentire composition is likely to be increased rapidly, and the curingreaction tends to be non-uniform. In order to minimize the difference inthe reactivity of the curable groups of both and to obtain a homogeneousbarrier portion, the curable group of the oligomer (A) may be selectedto be an acryloyloxy group having a relatively high reactivity, and thecurable group of the monomer (B) may be selected to be a methacryloyloxygroup having a relatively low reactivity.

The number average molecular weight of the oligomer (A) is from 30,000to 100,000, preferably from 40,000 to 80,000, more preferably from50,000 to 65,000. When the number average molecular weight of theoligomer (A) is within such a range, the viscosity of the barrierportion-forming photocurable resin composition can easily be adjusted tobe within the above-mentioned range.

The number average molecular weight of the oligomer (A) is a numberaverage molecular weight as calculated as polystyrene, obtained by themeasurement by GPC (gel permeation chromatography). Here, in themeasurement by GPC, in a case where a peak of the unreacted lowmolecular weight component (such as a monomer) appears, the numberaverage molecular weight is obtained by excluding such a peak.

The molecular weight of the monomer (B) is from 125 to 600, preferablyfrom 140 to 400, more preferably from 150 to 350. When the molecularweight of the monomer (B) is at least 125, volatilization of the monomer(B) can be prevented at the time of producing a display device by theafter-described reduced pressure lamination method. When the molecularweight of the monomer (B) is at most 600, it is possible to increase thesolubility of the monomer (B) in the high molecular weight oligomer (A),and it is possible to suitably carry out the viscosity adjustment as thebarrier portion-forming photocurable resin composition.

Oligomer (A)

The oligomer (A) is preferably one having an average of from 1.8 to 4curable groups per one molecule from the viewpoint of the curingproperty of the barrier portion-forming photocurable resin compositionand the mechanical properties of the barrier portion.

The oligomer (A) may, for example, be a urethane oligomer having aurethane bond, a poly(meth)acrylate of a polyoxyalkylene polyol, or apoly(meth)acrylate of a polyester polyol.

From such a viewpoint that the mechanical properties of the resin aftercuring, the adhesion with a surface material, etc. can widely beadjusted by the molecular weight design of the urethane chain, etc., aurethane oligomer prepared by using a polyol and a polyisocyanate as rawmaterials, is preferred, and the after-described urethane oligomer (A1)is more preferred. As the polyol, a polyoxyalkylene polyol is morepreferred.

Urethane Oligomer (A1)

A urethane oligomer (A1) having a number average molecular weight withina range of from 30,000 to 100,000 becomes to have a high viscosity, andit is difficult to synthesize by a usual method, and even if it can besynthesized, mixing it with the monomer (B) is difficult.

Therefore, it is preferred that the urethane oligomer (A1) issynthesized by a synthetic method using a monomer (B) (the followingmonomers (B1) and (B2)), and then, the obtained product is used as itis, as the barrier portion-forming photocurable resin composition, orthe obtained product is further diluted with the monomer (B) (thefollowing monomer (B1), (B3), etc.) and used as the barrierportion-forming photocurable resin composition.

(1) Monomer (B1): Among monomers (B), a monomer having a curable groupand not having a group reactive with an isocyanate group.

(2) Monomer (B2): Among monomers (B), a monomer having a curable groupand having a group reactive with an isocyanate group.

(3) Monomer (B3): Among monomers (B), a monomer having a curable groupand having a hydroxy group.

Synthetic Method for Urethane Oligomer (A1):

A method wherein in the presence of the monomer (B1) as a diluent, apolyol and a polyisocyanate are reacted to obtain a prepolymer having anisocyanate group, and then, the monomer (B2) is reacted to theisocyanate group of the prepolymer.

The polyol and the polyisocyanate may be known compounds, e.g. thepolyol (i) and the diisocyanate (ii), disclosed as raw materials for aurethane type oligomer (a) in WO2009/016943, which are incorporated inthis specification by reference.

The polyol (i) may, for example, be a polyoxyalkylene polyol such aspolyoxyethylene glycol or polyoxypropylene diol, a polyester polyol, apolycarbonate polyol, etc. Among them, a polyoxyalkylene polyol ispreferred, and polyoxypropylene polyol is particularly preferred. It isfurther preferred that some of oxypropylene groups in thepolyoxypropylene polyol are substituted by oxyethylene groups, wherebythe compatibility of the barrier portion-forming photocurablecomposition with other components, can be increased.

The isocyanate (ii) is preferably a diisocyanate selected from analiphatic diisocyanate, an alicyclic diisocyanate and a non-yellowingaromatic diisocyanate. Among them, examples of the aliphaticpolyisocyanate include hexamethylene diisocyanate,2,2,4-trimethyl-hexamethylene diisocyanate,2,4,4-trimethyl-hexamethylene diisocyanate, etc. Examples of thealicyclic polyisocyanate include isophorone diisocyanate, methylenebis(4-cyclohexyl isocyanate), etc. The non-yellowing aromaticdiisocyanate may, for example, be xylylene diisocyanate, etc. One ofthem may be used alone, or two or more of them may be used incombination.

The monomer (B1) may, for example, be an alkyl (meth)acrylate having aC₈₋₂₂ alkyl group (such as n-dodecyl (meth)acrylate, n-octadecyl(meth)acrylate or n-behenyl (meth)acrylate), or a (meth)acrylate havingan alicyclic hydrocarbon group (such as isobornyl (meth)acrylate oradamantyl (meth)acrylate).

The monomer (B2) may, for example, be a monomer having active hydrogen(a hydroxy group, an amino group, etc.) and a curable group.Specifically, a hydroxy alkyl (meth)acrylate having a C₂₋₆ hydroxyalkylgroup (such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl (meth)acrylate or 4-hydroxybutyl(meth)acrylate) may, for example, be mentioned, and a hydroxyalkylacrylate having a C₂₋₄ hydroxyalkyl group is preferred.

Monomer (B)

The monomer (B) is preferably one having from 1 to 3 curable groups perone molecule from the viewpoint of the curing property of the barrierportion-forming photocurable resin composition and the mechanicalproperties of the barrier portion.

The barrier portion-forming photocurable resin composition may contain,as the monomer (B), the monomer (B1) which is used as a diluent in theabove-describe synthetic method for the urethane oligomer (A1). Further,it may contain, as the monomer (B), an unreacted monomer (B2) which isused in the above-described synthetic method for the urethane oligomer(A1).

The monomer (B) preferably contains the monomer (B3) having a hydroxygroup from the viewpoint of the adhesion between the transparent surfacematerial and the barrier portion or the solubility of theafter-described various additives.

As the monomer (B3) having a hydroxy group, a hydroxy methacrylatehaving from 1 to 2 hydroxy groups and a C₃₋₈ hydroxyalkyl groups (suchas 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate,4-hydroxybutyl methacrylate or 6-hydroxyhexyl methacrylate) ispreferred, and 2-hydroxybutyl methacrylate is particularly preferred.

The content of the monomer (B) in the barrier portion-formingphotocurable resin composition is preferably from 15 to 50 mass %, morepreferably from 20 to 45 mass %, further preferably from 25 to 40 mass%, in the entirety (100 mass %) of the curable compound (I) i.e. thetotal (100 mass %) of the oligomer (A) and the monomer (B). When thecontent of the monomer (B) is at least 15 mass %, the curing property ofthe barrier portion-forming photocurable resin composition and theadhesion between the surface material and the barrier portion will begood. When the content of the monomer (B) is at most 50 mass %, theviscosity of the barrier portion-forming photocurable resin compositioncan easily be adjusted to be at least 500 Pa·s.

Further, in the synthesis of the urethane oligomer (A1), the monomer(B2) reacted with the isocyanate group of the prepolymer is present as apart of the oligomer (A) and therefore is not included in the content ofthe monomer (B) in the barrier portion-forming photocurable resincomposition. On the other hand, the monomer (B1) used as a diluent inthe synthesis of the urethane oligomer (A1) and the monomer (B) addedafter the synthesis of the urethane oligomer (A1) are included in thecontent of the monomer (B) in the barrier portion-forming photocurableresin composition.

Photopolymerization Initiator (C1)

As the photopolymerization initiator (C1) to be contained in the barrierportion-forming photocurable resin composition, a photopolymerizationinitiator of e.g. acetophenone type, ketal type, benzoin or benzoinether type, phosphine oxide type, benzophenone type, thioxanthone type,a quinone type or the like may be mentioned, and a photopolymerizationinitiator of acetophenone type, ketal type or benzoin ether type ispreferred. In a case where curing is carried out by means of a shortwavelength visible light, a photopolymerization initiator of phosphineoxide type is more preferred from the viewpoint of the absorptionwavelength region. By using two or more photopolymerization initiators(C1) different in the absorption wavelength region in combination, it ispossible to further accelerate the curing time or to increase thesurface hardness at the barrier portion.

The content of the photopolymerization initiator (C1) in a barrierportion-forming photocurable resin composition is preferably from 0.01to 10 parts by mass, more preferably from 0.1 to 5 parts by mass, per100 parts by mass of the entire curable compound (I) i.e. the total ofthe oligomer (A) and the monomer (B).

Additives

The barrier portion-forming photocurable resin composition may containvarious additives such as a polymerization inhibitor, a photo-curingaccelerator, a chain extender, a light stabilizer (such as anultraviolet absorber or a radical scavenger), an antioxidant, a flameretardant, an adhesion-improving agent (such as a silane couplingagent), a pigment, a dye, etc., as the case requires, and it preferablycontains a polymerization inhibitor, a light stabilizer, etc.Particularly, when a polymerization inhibitor is contained in an amountsmaller than the polymerization initiator, it is possible to improve thestability of the barrier portion-forming photocurable resin compositionand to adjust the molecular weight of the layer portion after curing.

As the polymerization inhibitor, a polymerization inhibitor of e.g.hydroquinone type (such as 2,5-di-tert-butylhydroquinone), catechol type(such as p-tert-butylcatechol), anthraquinone type, phenothiazine typeor hydroxy toluene type may be mentioned.

As the light stabilizer, an ultraviolet absorber (such as benzotriazoletype, benzophenone type or salicylate type) or a radical scavenger (suchas hindered amine type) may, for example, be mentioned.

As the antioxidant, a phosphorus type or sulfur type compound may bementioned.

The total amount of such additives is preferably at most 10 parts bymass, more preferably at most 5 parts by mass, per 100 parts by mass ofthe entire curable compound (I) i.e. the total of the oligomer (A) andthe monomer (B).

Step (b)

After step (a), a liquid first composition is supplied to a regionsurrounded by the uncured barrier portion.

In the present invention, the barrier portion in the steps (b) and (c)being “uncured” means that the barrier portion is not entirely cured,and one having partially cured or thickened by preliminarily applyinglight to the barrier portion for a short time, is also included in the“uncured” barrier portion.

The amount of the first composition to be supplied is preliminarily setto be such an amount that the space formed by the uncured barrierportion, the transparent surface material and the protective film isfilled by the first composition, and the distance between thetransparent surface material and the protective film is adjusted to be aprescribed distance (i.e. the layer portion is adjusted to have theprescribed thickness). At that time, it is desirable that a volumedecrease due to the curing shrinkage of the first composition is takeninto account. Accordingly, such an amount is preferably an amount suchthat the thickness of the first composition becomes slightly thickerthan the prescribed thickness of the layer portion.

As the supplying method, a method may be mentioned wherein thetransparent surface material is placed to be flat, and the compositionis supplied in a dot, line or strip pattern by a supplying means such asa dispenser or a die coater.

The viscosity of the first composition is preferably from 0.05 to 50Pa·s, more preferably from 1 to 20 Pa·s. When the viscosity is at least0.05 Pa·s, it is possible to suppress the proportion of theafter-described monomer (B′), and thereby to prevent deterioration ofthe physical properties of the layer portion. Further, as the lowboiling point component decreases, such being advantageous for theafter-described reduced pressure lamination method. When the viscosityis at most 50 Pa·s, air bubbles tend to less likely to remain in thelayer portion.

The viscosity of the first composition is measured at 25° C. by means ofan E-model viscometer.

The first composition may be a photocurable resin composition or aheat-curable resin composition. As the first composition, a photocurableresin composition comprising a curable compound and aphotopolymerization initiator (C′) is preferred from such a viewpointthat curing can be made at a low temperature, and the curing speed ishigh. Further, a high temperature is not required for the curing, andthe display panel is less likely to be damaged by a high temperature.

The layer portion-forming photocurable resin composition to be used asthe first composition in the present invention will be described.

Layer Portion-Forming Photocurable Resin Composition

The layer portion-forming photocurable resin composition is a liquidcomposition comprising a photocurable compound (II), aphotopolymerization initiator (C2) and a non-curable oligomer (D). Thenon-curable oligomer (D) is an oligomer having a hydroxy group whichdoes not undergo a curing reaction with the curable compound (II) in thecomposition at the time of curing the layer portion-forming photocurableresin composition.

Curable Compound (II)

The curable compound (II) in the layer portion-forming photocurableresin composition is composed of at least one curable compound whichundergoes a curing reaction at the time of curing the layerportion-forming photocurable resin composition, and at least one of saidat least one curable compound is a compound (IIa) having a hydroxy groupwhich is not reactive at the time of curing the layer portion-formingphotocurable resin composition.

When the curable compound (II) contains such a compound (IIa), hydroxygroups will be present in a cured product obtained by a curing reactionof the curable compound (II) alone. The presence of such hydroxy groupscontributes to the stabilization of the non-curable oligomer in thelayer portion-forming photocurable resin composition.

Therefore, the compound (IIa) having a hydroxy group which is notreactive at the time of curing may be one such that unreacted hydroxygroups remain after the curing reaction, and for example, some ofhydroxy groups in the compound (IIa) may undergo a curing reaction, solong as the rest of hydroxy groups will remain in an unreacted statewithout undergoing a curing reaction.

Such a compound (IIa) having a hydroxy group which is not reactive atthe time of curing may be one having a hydroxy group as well as acurable group which contributes to the curing reaction, and it may be amonomer or an oligomer having repeating units. With a view tofacilitating the adjustment of the viscosity of the photocurablecomposition in an uncured state, it is preferred to use, as the compound(IIa), a monomer having a curable group and a hydroxy group.

The curable compound (II) preferably comprises at least one oligomer(A′) having a curable group and having a number average molecular weightof from 1,000 to 100,000, and at least one monomer (B′) having a curablegroup and having a molecular weight of from 125 to 600. By using such acurable compound (II), the viscosity of the layer portion-formingphotocurable resin composition can easily be adjusted to be within theabove-mentioned preferred range.

In such a case, it is preferred to use, as at least a part of themonomer (B′), a monomer (B3) having a curable group and a hydroxy groupand having a molecular weight of from 125 to 600.

The curable group in the oligomer (A′) or the monomer (B′) may, forexample, be an addition-polymerizable unsaturated group (such as anacryloyloxy group or a methacryloyloxy group), or a combination of anunsaturated group and a thiol group, and a group selected from anacryloyloxy group and a methacryloyloxy group is preferred from such aviewpoint that the curing speed is high, and a layer portion having hightransparency is obtainable.

The curable group in the oligomer (A′) and the curable group in themonomer (B′) may be the same or different from each other. The curablegroup in the oligomer (A′) having a relatively high molecular weighttends to have a lower reactivity than the curable group in the monomer(B′) having a relatively low molecular weight, whereby curing of themonomer (B′) tends to advance, and the viscosity of the entirecomposition is likely to rapidly increase, so that the curing reactiontends to be non-uniform. In order to minimize the difference in thereactivity between the two curable groups and to obtain a uniform layerportion, it is more preferred that the curable group in the oligomer(A′) is selected to be an acryloyloxy group having a relatively highreactivity, and the curable group in the monomer (B′) is selected to bea methacryloyloxy group having a relatively low reactivity.

Oligomer (A′)

The number average molecular weight of the oligomer (A′) is from 1,000to 100,000, preferably from 10,000 to 70,000. When the number averagemolecular weight of the oligomer (A′) is within such a range, theviscosity of the layer portion-forming photocurable resin compositioncan easily be adjusted to be within the above-mentioned range.

The number average molecular weight of the oligomer (A′) is a numberaverage molecular weight as calculated as polystyrene, obtained by themeasurement by GPC. Further, in the measurement by GPC, in a case wherea peak of an unreacted low molecular weight component (such as amonomer) appears, the number average molecular weight is obtained byexcluding such a peak.

The oligomer (A′) is preferably one having an average of from 1.8 to 4curable groups per one molecule from the viewpoint of curing property ofthe layer portion-forming photocurable resin composition and themechanical properties of the layer portion.

The oligomer (A′) may, for example, be a urethane oligomer having aurethane bond, a poly(meth)acrylate of a polyoxyalkylene polyol, or apoly(meth)acrylate of a polyester polyol, and a urethane oligomer (A2)is preferred from such a viewpoint that the mechanical properties of theresin after curing, the adhesion to the surface material, etc. canwidely be adjusted by e.g. molecular design of the urethane chain.

The urethane oligomer (A2) is preferably one to be synthesized by amethod wherein a polyol and a polyisocyanate are reacted to obtain aprepolymer having an isocyanate group, and then, the above monomer (B2)is reacted to the isocyanate group of the prepolymer.

The polyol and the polyisocyanate may be known compounds, e.g. thepolyol (i) and the diisocyanate (ii) disclosed as raw materials for aurethane type oligomer (a) disclosed in WO2009/016943, which areincorporated in this specification by reference.

The content of the oligomer (A′) is preferably from 20 to 90 mass %,more preferably from 30 to 80 mass %, in the entirety (100 mass %) ofthe curable compound (II) i.e. the total (100 mass %) of the oligomer(A′) and the monomer (B′). When the content of the oligomer (A′) is atleast 20 mass %, the heat resistance of the layer portion becomes good.When the content of the oligomer (A′) is at most 90 mass %, the curingproperty of the layer portion-forming photocurable resin composition andthe adhesion between the surface material and the layer portion becomegood.

Monomer (B′)

The molecular weight of the monomer (B′) is from 125 to 600, preferablyfrom 140 to 400. When the molecular weight of the monomer (B′) is atleast 125, volatilization of the monomer can be prevented at the time ofproducing a display device by the after-described reduced pressurelamination method. When the molecular weight of the monomer (B′) is atmost 600, the adhesion between the surface material and the layerportion becomes good.

The monomer (B′) is preferably one having from 1 to 3 curable groups perone molecule from the viewpoint of the curing property of the layerportion-forming photocurable resin composition and the mechanicalproperties of the layer portion.

The content of the monomer (B′) is preferably from 10 to 80 mass %, morepreferably from 20 to 70 mass % in the entirety (100 mass %) of thecurable compound (II) i.e. the total (100 mass %) of the oligomer (A′)and the monomer (B′).

The monomer (B′) preferably contains a monomer (B3) having a curablegroup and a hydroxy group. The monomer (B3) contributes to stabilizationof the non-curable oligomer (D). Further, when the monomer (B3) iscontained, good adhesion between the transparent surface material and alayer portion tends to be readily obtainable.

As the monomer (B3) having a hydroxy group, the same one as the monomer(B3) in the barrier portion-forming photocurable resin composition maybe mentioned, and 2-hydroxybutyl methacrylate is particularly preferred.

The content of the monomer (B3) is preferably from 10 to 60 mass %, morepreferably from 20 to 50 mass %, in the entirety (100 mass %) of thecurable compound (II) i.e. the total (100 mass %) of the oligomer (A′)and the monomer (B′). When the content of the monomer (B3) is at least10 mass %, it is readily possible to sufficiently obtain the effects toimprove the stability of the layer portion-forming photocurable resincomposition and to improve the adhesion between the surface material andthe layer portion.

The monomer (B′) preferably contains the following monomer (B4). Themonomer (B4) contributes to shortening of the time from bonding thedisplay panel and the adhesive layer-equipped transparent surfacematerial in a reduced pressure atmosphere to disappearance of voidsformed in the adhesive layer after returning the atmosphere to anatmospheric pressure atmosphere.

On the other hand, if the monomer (B4) is contained, the time requiredfor curing the layer portion-forming photocurable resin compositiontends to be long.

Monomer (B4): At least one member selected from alkyl methacrylateshaving a C₈₋₂₂ alkyl group.

The monomer (B4) may, for example, be n-dodecyl methacrylate,n-octadecyl methacrylate or n-behenyl methacrylate, and n-dodecylmethacrylate or n-octadecyl methacrylate is preferred.

The content of the monomer (B4) is preferably from 5 to 50 mass %, morepreferably from 15 to 40 mass %, in the entirety (100 mass %) of thecurable compound (II) i.e. the total (100 mass %) of the oligomer (A′)and the monomer (B′). When the content of the monomer (B4) is at least 5mass %, an adequate effect of adding the monomer (B4) is easilyobtainable.

Further, in the mass ratio of the content of the monomer (B4) to thecontent of the monomer (B3) having a hydroxy group, the larger theproportion of the monomer (B4), the better to let voids formed in theadhesive layer readily disappear at the time of bonding the displaypanel and the adhesive layer-equipped transparent surface material in areduced pressure atmosphere and then returning the atmosphere to theatmospheric pressure atmosphere, and the upper limit value in the rangeof the shear modulus of the layer portion tends to be slightly higher.

For example, in a case where the layer portion-forming photocurableresin composition contains the monomer (B3) having a hydroxy group andthe monomer (B4) having an alkyl group, the content of the monomer (B4)is from 0.6 to 2.5 to 1 of the content (based on mass) of the monomer(B3), and no chain transfer agent is contained, the shear modulus of thelayer portion is more preferably from 0.8 to 25 kPa, particularlypreferably from 0.8 to 12 kPa.

Further, addition of a chain transfer agent contributes to an increaseof the upper limit value of the preferred range of the shear modulus ofthe layer portion. For example, in a case where the layerportion-forming photocurable resin composition contains a chain transferagent in a range of at most 1 part by mass per 100 parts by mass of theentire curable compound (II), and the content of the monomer (B4) issmaller than the monomer (B3), the shear modulus of the layer portion ismore preferably from 0.8 to 12 kPa, particularly preferably from 0.8 to6 kPa.

In a case where the content of the monomer (B4) is from 1 to 3 to 1 ofthe content (based on mass) of the monomer (B3), and a chain extender iscontained in a range of at most 1 part by mass per 100 parts by mass ofthe entire curable compound (II), the shear modulus of the layer portionis more preferably from 0.8 to 75 kPa, particularly preferably from 0.8to 12 kPa.

Photopolymerization Initiator (C2)

As the photopolymerization initiator (C2) contained in the layerportion-forming photocurable resin composition, a photopolymerizableinitiator of e.g. acetone type, ketal type, benzoin or benzoin ethertype, phosphine oxide type, benzophenone type, thioxanthone type orquinone type may be mentioned, and a photopolymerization initiator ofphosphine oxide type or thioxanthone type is preferred. With a view topreventing coloration after the photopolymerization reaction, phosphineoxide type is particularly preferred.

The content of the photopolymerization initiator (C2) in the layerportion-forming photocurable resin composition is preferably from 0.01to 10 parts by mass, more preferably from 0.1 to 5 parts by mass, per100 parts by mass of the entirety of the curable compound (II) i.e. thetotal of the oligomer (A′) and the monomer (B′).

Non-Curable Oligomer (D)

The non-curable oligomer (D) is an oligomer which does not undergo acuring reaction with the curable compound (II) in the composition at thetime of curing the layer portion-photocurable resin composition andwhich has a hydroxy group.

The number of hydroxy groups per one molecule of the non-curableoligomer (D) is preferably from 0.8 to 3, more preferably from 1.8 to2.3.

The number average molecular weight (Mn) per one hydroxy group of thenon-curable oligomer (D) is preferably from 400 to 8,000. When thenumber average molecular weight per one hydroxy group is at least 400,the polarity of the non-curable oligomer (D) will not be too high, andgood compatibility with the curable compound (II) in the layerportion-forming photocurable resin composition is readily obtainable.When the number average molecular weight per one hydroxy group is atmost 8,000, it is readily possible to obtain the effect to stabilize thenon-curable oligomer (D) in the layer portion after curing by aninteraction between the hydroxy group derived from the curable compound(II) and the hydroxy group of the non-curable oligomer (D). It isconsidered that a hydrogen bond contributes to such an interaction.

One of such non-curable oligomers (D) may be used alone, or two or moreof them may be used in combination.

As an example of the non-curable oligomer (D) having a hydroxy group, apolyol having a high molecular weight may, for example, be mentioned,and a polyoxyalkylene polyol, a polyester polyol or a polycarbonatepolyol is preferred.

The polyoxyalkylene polyol may, for example, be a polyoxyalkylene diolsuch as polyoxyethylene glycol, polyoxypropylene diol, polyoxypropylenetriol or polyoxytetramethylene glycol.

The number average molecular weight (Mn) per one hydroxy group of thepolyoxyalkylene polyol is preferably from 400 to 8,000, more preferablyfrom 600 to 5,000.

The polyester polyol may be an aliphatic polyester diol having aresidual group of an aliphatic diol such as ethylene glycol, propyleneglycol or 1,4-butanediol and a residual group of an aliphaticdicarboxylic acid such as glutaric acid, adipic acid or sebacic acid.

The polycarbonate polyol may be an aliphatic polycarbonate diol having adiol residual group such as 1,6-hexanediol, or an aliphaticpolycarbonate diol such as a ring-opened polymer of an alicycliccarbonate.

The number average molecular weight (Mn) per one hydroxy group of thepolyester polyol or the polycarbonate polyol is preferably from 400 to8,000, more preferably from 800 to 6,000.

In this specification, the number average molecular weight of thenon-curable oligomer (D) is a value calculated by the following formula(1) from the hydroxy value A (KOH mg/g) measured in accordance with JISK1557-1 (2007 edition) and the number B of hydroxy groups in onemolecule of the non-curable oligomer (D).

Molecular weight of non-curable oligomer (D)=56.1×B×1,000/A   (1)

From such a viewpoint that the elastic modulus of the layer portionafter curing can easily be made lower, it is preferred to use, as thenon-curable oligomer (D), a polyoxyalkylene polyol, and apolyoxypropylene polyol is particularly preferred. Further, some ofoxypropylene groups in the polyoxypropylene polyol may be substituted byoxyethylene groups.

For example, from the viewpoint of the compatibility, it is preferredthat the oligomer (A′) is a urethane oligomer synthesized by using apolyoxyalkylene polyol and a polyisocyanate as raw materials, and thenon-curable oligomer (D) is a polyoxyalkylene polyol.

In the present invention, in order to stabilize the layerportion-forming photocurable resin composition in an uncured state andto prevent separation of the non-curable oligomer (D) from the layerportion after curing, it is preferred that the oligomer (A′) and thenon-curable oligomer (D) have molecular chains having the same orsimilar structures.

Specifically, it is preferred not only to use compound having a hydroxygroup such as a polyol (hereinafter sometimes referred to also as ahydroxy group-containing compound) as a raw material at the time ofsynthesizing the oligomer (A′) in the layer portion-forming photocurableresin composition, but also to use the same hydroxy group-containingcompound as the non-curable oligomer (D).

For example, in a case where the oligomer (A′) is a urethane oligomersynthesized by using a polyoxyalkylene polyol and a polyisocyanate asraw materials, it is preferred to use such a polyoxyalkylene polyol asthe non-curable oligomer (D).

Otherwise, in a case where the hydroxy group-containing compound as araw material for the oligomer (A′) and the hydroxy group-containingcompound to be used as the non-curable oligomer (D) are not the same, itis preferred to adjust so that the molecular chains of both havepartially common structures such as common repeating units, and thepolarities of both are made to be substantially equal. The method foradjusting the polarity may, for example, be a method of introducing apolar group to increase the polarity, a method of substituting some ofoxypropylene groups by oxyethylene groups to increase the polarity, or amethod of reducing the molecular weight per one hydroxy group toincrease the polarity. A combination of these methods may also be used.

For example, in a case where the oligomer (A′) is a urethane oligomersynthesized by using a polyoxypropylene polyol (a′) having some ofoxypropylene groups substituted by oxyethylene groups, and apolyisocyanate, as raw materials, it is preferred to use, as thenon-curable oligomer (D), a polyoxypropylene polyol which is apolyoxypropylene polyol having no oxyethylene group and which has amolecular weight per one hydroxy group being smaller than the abovepolyol (a′).

One example of the most preferred layer portion-forming photocurableresin composition may be a composition comprising, as the oligomer (A′)a urethane oligomer (A2) obtainable by reacting a polyisocyanatecompound with a polyoxypropylene diol having some of oxypropylene groupssubstituted by oxyethylene groups to obtain a prepolymer having anisocyanate group, followed by a reaction with the above monomer (B2), asthe non-curable oligomer (D) a polyoxypropylene diol having some ofoxypropylene groups substituted by oxyethylene groups, which is the sameas the raw material for the urethane oligomer (A2), and as the monomer(B′) a monomer (B3) having a hydroxy group.

Thus, it is considered that if the oligomer (A′) partially has the samemolecular structure as the non-curable oligomer (D), the compatibilityof the non-curable oligomer (D) in the compound is further increased,and further, as the monomer (B′) has a hydroxy group, the non-curableoligomer (D) can be stably present in the cured product due to theinteraction between the hydroxy group in the molecular structure aftercuring the curable compound (II) and the hydroxy group in the molecularstructure of the non-curable oligomer (D).

Further, as another example, also in the case of a compositioncomprising as the oligomer (A′) a urethane oligomer (A2) obtainable byreacting a polyisocyanate compound with a polyoxypropylene diol havingsome of oxypropylene groups substituted by oxyethylene groups to obtaina prepolymer having an isocyanate group, followed by a reaction with theabove monomer (B2), as the non-curable oligomer (D) a polyoxypropylenediol not substituted by oxyethylene groups and having a molecular weightsmaller than the oxypropylene diol as the raw material for the urethaneoligomer (A2), and as the monomer (B′) a monomer (B3) having a hydroxygroup, it is possible to obtain good compatibility of the non-curableoligomer (D) in the composition, and it is possible to let thenon-curable oligomer (D) be present stably in the cured product.

If the content of the non-curable oligomer (D) in the layerportion-forming photocurable resin composition increases, the shearmodulus of the layer portion tends to decrease. On the other hand, ifthe content of the non-curable oligomer (D) is too much, curing of thelayer portion in the adhesive layer tends to be inadequate. If thecuring of the layer portion is inadequate, it is likely to be difficultto peel the protective film from the adhesive layer after curing.

Therefore, the content of the non-curable oligomer (D) in the layerportion-forming photocurable resin composition is preferably set withina range of from 10 to 70 mass % in the entirety (100 mass %) of thelayer portion-forming photocurable resin composition also inconsideration of the balance with other components in order not to causesuch problems.

For example, in a case where the layer portion-forming photocurableresin composition comprises the above monomer (B3) having a hydroxygroup and the monomer (B4) having an alkyl group, wherein the content ofthe monomer (B4) is from 0.6 to 2.5 per 1 of the content (based on mass)of the monomer (B3), and no chain extender is contained, the content ofthe non-curable oligomer (D) is preferably from 30 to 70 mass %, morepreferably from 40 to 70 mass %, in the entirety (100 mass %) of thelayer portion-forming photocurable resin composition.

Further, also addition of a chain extender contributes to reducing theshear modulus of the layer portion. In a case where the layerportion-forming photocurable resin composition contains a chain extenderwithin a range of at most 1 part by mass per 100 parts by mass of theentire curable compound (II), and the content of the monomer (B4) isless than the monomer (B3), the content of the non-curable oligomer (D)is preferably from 40 to 70 mass %, more preferably from 50 to 70 mass%, in the entirety of the layer portion-forming photocurable resincomposition.

In a case where the content of the monomer (B4) is from 1 to 3 per 1 ofthe content (based on mass) of the monomer (B3), and a chain extender iscontained within a range of at most 1 part by mass per 100 parts by massof the entire curable compound (II), the content of the non-curableoligomer (D) is preferably from 5 to 55 mass %, more preferably from 10to 50 mass %, further preferably from 35 to 50 mass %, in the entiretyof the layer portion-forming photocurable resin composition.

If the monomer (B4) or the chain extender is added, the curing speedtends to be slow, and from such a viewpoint, the content thereof shouldbetter be small. In a case where the mass ratio of the content of themonomer (B4) to 1 of the content (based on mass) of the monomer (B3) isless than 0.6, and no chain extender is contained, the content of thenon-curable oligomer (D) is preferably from 40 to 70 mass %, morepreferably from 50 to 70 mass %.

Additives

In addition to the curable compound (II), the non-curable oligomer (D)and the photopolymerization initiator (C), the layer portion-formingphotocurable resin composition may contain, as the case requires,various additives such as a polymerization inhibitor, a photo-curingaccelerator, a chain extender, a light stabilizer (such as anultraviolet absorber or a radical scavenger), an antioxidant, a flameretardant, an adhesion-improving agent (such as a silane couplingagent), a pigment, a dye, etc. and it is preferred that the compositioncontains a polymerization inhibitor, a light stabilizer, etc. Especiallywhen a polymerization inhibitor is contained in an amount smaller thanthe polymerization initiator, it is possible to improve the stability ofthe layer portion-forming photocurable resin composition, and it ispossible to adjust the molecular weight of the layer portion aftercuring.

The total amount of such additives is preferably at most 10 parts bymass, more preferably at most 5 parts by mass, per 100 parts by mass ofthe entirety of the curable compound (II) i.e. the total of the oligomer(A′) and the monomer (B′).

Among additives, the chain extender is preferably not contained orcontained only in a small amount with a view to obtaining a good curingspeed. When a chain extender is contained, the shear modulus of thelayer portion tends to decrease, whereby it becomes possible to reducethe amount of the non-curable oligomer (D) required to bring the shearmodulus of the layer portion to a preferred value. If the amount of thenon-curable oligomer (D) is small, the difference in the curingshrinkage between the barrier portion and the layer portion tends to besmall.

In a case where a chain extender is contained, its amount is preferablyat most 1 part by mass, more preferably at most 0.5 part by mass, per100 parts by mass of the entirety of the curable compound (II) i.e. thetotal of the oligomer (A′) and the monomer (B′).

Step (c)

After step (b), the transparent surface material having the firstcomposition supplied thereto is put in a pressure reducing device, andthe transparent surface material is placed flatly on a fixed supportplaten in the pressure reducing device so that the surface of the firstcomposition faces upward.

At an upper portion in the pressure reducing device, a verticallymovable support mechanism is provided, and a supporting surface material(such as a glass plate) is attached to the movable support mechanism. Onthe lower surface of the supporting surface material, a protective filmis bonded.

The supporting surface material is located at a position above thetransparent surface material and not to contact with the firstcomposition. That is, the first composition on the transparent surfacematerial and the protective film on the surface of the supportingsurface material are permitted to face each other without being incontact with each other.

Here, the vertically movable support mechanism may be provided at alower portion in the pressure reducing device, and the transparentsurface material having the first composition supplied thereto, may beplaced on the movable support mechanism. In such a case, the supportingsurface material may be attached to the fixed support platen provided atan upper portion in the pressure reducing device, so that thetransparent surface material and the supporting surface material faceeach other.

Otherwise, both the transparent surface material and the supportingsurface material may be supported by the movable support mechanismsprovided at the upper and lower portions in the pressure reducingdevice.

After placing the transparent surface material and the supportingsurface material at the predetermined positions, the interior of thepressure reducing device is evacuated to form a predetermined reducedpressure atmosphere. If possible, during the pressure reducing operationor after forming a predetermined reduced pressure atmosphere, thetransparent surface material and the supporting surface material may bemoved to the predetermined position in the pressure reducing device.

After the interior of the pressure reducing device becomes apredetermined reduced pressure atmosphere, the supporting surfacematerial supported by the movable support mechanism is moved downward,and the supporting surface material having a protective film bondedthereto is overlaid on the first composition on the transparent surfacematerial so that the protective film is in contact with the firstcomposition.

By such overlaying, the first composition is sealed in a space enclosedby the surface of the transparent surface material, the surface of theprotective film bonded to the supporting surface material and theuncured barrier portion.

At the time of overlaying, the first composition is pressed and spreadby the self weight of the supporting surface material and the pressingpressure from the movable support mechanism, etc., and the firstcomposition is filled in the above space to form an uncured layerportion. Thereafter, at the time of exposure to a high pressureatmosphere in step (d), an uncured layer portion having no or littlevoids will be formed.

The reduced pressure atmosphere at the time of overlaying is at most 100Pa, preferably from 10 to 100 Pa, more preferably from 15 to 40 Pa. Ifthe reduced atmosphere is too much low pressure, an adverse effect islikely to be given to various components (such as a curable compound, aphotopolymerization initiator, a polymerization inhibitor, a chainextender, a light stabilizer, etc.) contained in the first composition.For example, if the reduced pressure atmosphere is too low pressure, therespective components are likely to volatize, and it may take time toprovide a reduced pressure atmosphere.

The period of time from the time when the transparent surface materialand the supporting surface material are laminated to the release of thereduced pressure atmosphere, is not particularly limited, and aftersealing the first composition, the reduced pressure atmosphere mayimmediately be released, or after sealing the first composition, thereduced pressure state may be maintained for a predetermined period oftime. By maintaining the reduced pressure state for a predeterminedperiod of time, the first composition flows in the sealed space, wherebythe distance between the transparent surface material and the protectivefilm bonded to the supporting surface material becomes uniform, and itbecomes easy to maintain the sealed state even if the pressure of theatmosphere is increased. The period of time to maintain the reducedpressure state may be a long time of at least a few hours, but from theviewpoint of the production efficiency, it is preferably within onehour, more preferably within 10 minutes.

In the process of the present invention, in a case where a secondcomposition having a high viscosity is applied to form an uncuredbarrier portion, the thickness of the first composition in the laminateobtained in step (c) can be made to be relatively thick at a level offrom 0.03 to 2 mm.

Step (d)

After releasing the reduced pressure atmosphere in step (c), thelaminate is held in an elevated pressure atmosphere of at least 50 kPa.

When the laminate is held in an elevated pressure atmosphere of at least50 kPa, by the elevated pressure, the transparent surface material andthe supporting surface material are pressed in the direction foradhesion, whereby if voids are present in the sealed space in thelaminate, an uncured layer portion will flow in the voids, and theentire sealed space will be uniformly filled with an uncured layerportion.

The elevated pressure atmosphere is usually from 80 to 120 kPa. Theelevated pressure atmosphere may be an atmospheric pressure atmosphereor an atmosphere under a higher pressure. An atmospheric pressureatmosphere is most preferred in that an operation such as curing of theuncured layer portion can be carried out without requiring any specialinstallation.

The period of time (hereinafter referred to as the high pressureretention time) from the time when the laminate is held under anelevated pressure atmosphere of at least 50 kPa to the initiation ofcuring of the uncured layer portion, is not particularly limited. In acase where a process of taking out the laminate from the pressurereducing device, transferring it to a curing device and initiating thecuring, is carried out in an atmospheric pressure atmosphere, the timerequired for the process becomes the high pressure retention time.Therefore, in a case where at the time when the laminate is placed in anatmospheric air atmosphere, voids are no longer present in the sealedspace of the laminate, or in a case where voids have disappeared duringthe process, the uncured layer portion can immediately be cured. In acase where it takes time until voids will disappear, the laminate isheld in an atmosphere under a pressure of at least 50 kPa until voidswill disappear. Further, even if the high retention time becomes long,usually, there will no trouble, and therefore, the high pressureretention time may be prolonged depending upon other necessities for theprocess. The high temperature retention time may be as long as more thanone day, but from the viewpoint of the production efficiency it ispreferably within 6 hours, more preferably within one hour, particularlypreferably within 10 minutes, since the production efficiency will behigher.

Then, by curing the uncured layer portion and the uncured barrierportion, an adhesive layer having a layer portion and a barrier portionwill be formed. At that time, the uncured barrier portion may be curedat the same time as curing the uncured layer portion, or maypreliminarily be cured prior to curing the uncured layer portion.

In a case where the uncured layer portion and the uncured barrierportion are made of photocurable compositions, curing is carried out byapplying light. For example, from a light source (such as an ultravioletlamp, a high pressure mercury lamp or UV-LED) ultraviolet light orvisible light with a short wavelength is applied to cure thephotocurable resin compositions.

The light is preferably ultraviolet light or visible light with awavelength of at most 450 nm.

In a case where a light-shielding printed portion is formed along theperipheral portion of the transparent surface material, or in a casewhere an antireflection layer is provided on the transparent surfacematerial, and such an antireflection layer or a transparent resin filmhaving such an antireflection layer formed or the adhesive layerprovided between the antireflection film and the transparent surfacematerial, will not permit ultraviolet ray to pass therethrough, light isapplied from the side of the supporting surface material.

In a case where the uncured layer portion is made of a photocurablecomposition and if sufficiently photo-cured, a suitable shear modulus ofelasticity will not be obtainable, application of light may be stoppedduring the curing to form the layer portion, and after bonding it toanother surface material (a display panel), the layer portion may beirradiated again with light or heated to accelerate the curing of thelayer portion. In a case where the curing is accelerated by heating, avery small amount of a thermal polymerization initiator may beincorporated to the photocurable composition. Even in a case where athermal polymerization initiator is not incorporated, by maintainingheating after an incomplete photocuring, the cured state of the layerportion can be stabilized, such being preferred. The process of thepresent invention is carried out usually at a low temperature at which afilm is durable, such being advantageous from the viewpoint of theprotection of the protective film.

Step (e)

The supporting surface material is removed from the protective film toobtain an adhesive layer-equipped transparent surface material whereinan adhesive layer having a sufficient adhesion is preliminarily formedon a transparent surface material, and formation of voids at theinterface between the transparent surface material and the adhesivelayer is sufficiently prevented.

Specific Example

Now, the process for producing an adhesive layer-equipped transparentsurface material 1 in FIG. 1 will be specifically described withreference to the drawings.

Step (a)

As shown in FIGS. 2 and 3, a barrier portion-forming photocurable resincomposition is applied by a dispenser (not shown) or the like along alight-shielding printed portion 12 at the peripheral portion of aprotective plate 10 (a transparent surface material).

Step (b)

Then, as shown in FIGS. 4 and 5, a layer portion-forming photocurableresin composition 26 is supplied to a rectangular region 24 surroundedby an uncured barrier portion 22 on the protective plate 10. The amountof the layer portion-forming photocurable resin composition 26 to besupplied, is preliminarily set to be an amount such that the space to besealed by the uncured barrier portion 22, the protective plate 10 andthe protective film 16 (see FIG. 6), is filled by the layerportion-forming photocurable resin composition 26.

Supplying of the layer portion-forming photocurable resin composition 26is carried out in such a manner that as shown in FIGS. 4 and 5, theprotective plate 10 is placed flatly on the lower platen 28, and bymeans of a horizontally moving dispenser 30, the layer portion-formingphotocurable resin composition 26 is supplied in a line, strip ordot-form.

The dispenser 30 is made to be horizontally movable in the entire rangeof the region 24 by a known horizontal movement mechanism comprising apair of feed screws 32 and a feed screw 34 perpendicular to the feedscrews 32. Here, instead of the dispenser 30, a die coater may be used.

Step (c)

Then, as shown in FIG. 6, the protective plate 10 and the supportingsurface material 36 having the protective film 16 bonded thereto, arebrought in a pressure reducing device 38. At an upper portion in thepressure reducing device 38, an upper platen 42 having a plurality ofsuction pads 40 is disposed, and at a lower portion, a lower platen 44is provided. The upper platen 42 is made to be vertically movable by anair cylinder 46.

The supporting surface material 36 is attached to the suction pads 40 sothat the surface having the protective film 16 bonded thereto facesdownward. The protective plate 10 is fixed on the lower platen 44 sothat the surface having the layer portion-forming photocurable resincomposition 26 supplied thereto faces upward.

Then, the air in the pressure reducing device 38 is suctioned by avacuum pump 48. After the atmosphere pressure in the pressure reducingdevice 38 has reached, for example, a reduced pressure atmosphere offrom 15 to 40 Pa, the air cylinder 46 is operated to let the supportingsurface material 36 descend towards the protective plate 10 waitingbelow, in such a state as suction-held by suction pads 40 of the upperplaten 42. And, the protective plate 10 and the supporting surfacematerial 36 having the protective film 16 bonded thereto, are laminatedvia the uncured barrier portion 22 to constitute a laminate wherein theuncured layer portion made of the layer portion-forming photocurableresin composition 26 is sealed by the protective plate 10, theprotective film 16 and the uncured barrier portion 22, and the laminateis maintained in a reduced pressure atmosphere for a predeterminedperiod of time.

The attaching position of the protective plate 10 to the lower platen44, the number of suction pads 40, the attaching position of thesupporting surface material 36 to the upper platen 42, etc. are suitablyadjusted depending upon the sizes, shapes, etc. of the protective plate10 and the supporting surface material 36. At that time, by usingelectrostatic chucks as the suction pads and adopting the electrostaticchuck-holding method as disclosed in WO2010/016588 (which isincorporated in this specification by reference), the supporting surfacematerial 36 can be held stably in a reduced pressure atmosphere.

Step (d)

Then, inside of the pressure reducing device 38 is made to be e.g. anatmospheric pressure atmosphere, and then, the laminate is taken outfrom the pressure reducing device 38. When the laminate is placed in anatmospheric pressure atmosphere, the surface on the protective plate 10side and the surface on the supporting surface material 36 side of thelaminate are pressed by the atmospheric pressure, whereby the uncuredlayer portion in the sealed space is pressed by the protective plate 10and the supporting surface material 36. By such a pressure, the uncuredlayer portion in the sealed space will flow, and the entire sealed spacewill be uniformly filled with the uncured layer portion.

Then, from the supporting surface material 36 side, light (ultravioletlight or visible light with a short wavelength) is applied to theuncured barrier portion 22 and the uncured layer portion to cure theuncured barrier portion 22 and the uncured layer portion in the laminatethereby to form an adhesive layer having a layer portion and a barrierportion.

Step (e)

Then, the supporting surface material 36 is removed from the protectivefilm 16 to obtain an adhesive layer-equipped transparent surfacematerial 1.

Advantageous Effects

According to the process for producing an adhesive layer-equippedtransparent surface material of the present invention, it is possible toproduce an adhesive layer-equipped transparent surface material having arelatively large area without forming voids at the interface between theadhesive layer and the transparent surface material or the protectivefilm. Even if voids remain in the uncured layer portion sealed underreduced pressure, the volume of such voids decreases, and the voids willeasily disappear in a high temperature atmosphere before curing, as thepressure is exerted also to the sealed uncured layer portion. Forexample, the volume of a gas in voids in the uncured layer portionsealed under 100 Pa is considered to become 1/1,000 under 100 kPa. Thegas may be dissolved in the uncured layer portion, and the gas in voidshaving a very small volume will readily be dissolved in the uncuredlayer portion and will disappear.

Further, as compared with a method (an injection method) of injecting aflowable curable resin composition into a space in a shallow and a widearea between two sheets of surface materials, formation of voids isless, and the first composition can be filled in a short time. Yet,there is little restriction with respect to the viscosity of the firstcomposition, and the first composition having a high viscosity caneasily be filled. Therefore, it is possible to employ a firstcomposition having a high viscosity containing a curable compound havinga relatively high molecular weight which is likely to reduce the shearmodulus of the layer portion.

In the adhesive layer-equipped transparent surface material of thepresent invention, an adhesive layer is preliminarily formed on at leastone surface of a transparent surface material, whereby the step ofbonding with another surface material (such as a display panel) may beonly once, and bonding with another surface material (such as a displaypanel) is simple.

Further, the adhesive layer comprises a layer portion spreading over thesurface of the transparent surface material and a barrier portionsurrounding the periphery of the layer portion, whereby the thickness ofthe layer portion 18 can easily be made uniform. In the absence of sucha barrier portion, the peripheral portion of the layer portion tends tobe thin as compared with the center portion. As the uniformity inthickness of the layer portion 18 is high, formation of voids can wellbe prevented at the time of bonding a display panel and the adhesivelayer-equipped transparent surface material.

Further, when the display panel and the adhesive layer-equippedtransparent surface material are bonded in a reduced pressure atmosphereand then returned to an atmospheric pressure atmosphere, the volume ofvoids will decrease, and the voids will disappear, by the differentialpressure between the pressure (reduced pressure) in the voids formed atthe interface between the adhesive layer and the display panel and thepressure (atmospheric pressure) exerted to the adhesive layer.

At that time, if it takes a long time until the voids disappear, theremay be a case where it becomes difficult to confirm the bonding qualityin the bonding step. However, in the adhesive layer-equipped transparentsurface material of the present invention, the shear modulus of thelayer portion is within a specific range, whereby the molecular mobilityof the layer portion in contact with voids can easily be increased,whereby such voids will disappear in a short time, whereby the qualitycontrol is easy, and the productivity is high, such being desirable.

Further, the layer portion is supported by the transparent surfacematerial (such as a glass plate), and the shape can sufficiently bemaintained even if the shear modulus is at a low value within the rangeof the present invention.

Further, according to the present invention, a relatively thick adhesivelayer can be formed while maintaining the uniformity of the thickness,on the surface of the transparent surface material having a large area,whereby with the obtainable adhesive layer-equipped transparent surfacematerial, formation of voids can sufficiently be prevented even whenbonded to another surface material (such as a display panel) having alarge area which is likely to be deflected.

Further, when it has a removable protective film covering the surface ofthe adhesive layer, the shape of the adhesive layer can sufficiently bemaintained until immediately before being bonded to the display panel.

The adhesive layer-equipped transparent surface material as described inthe foregoing, is suitable as a protective plate for a display device.

Display Device

FIG. 7 is a cross-sectional view illustrating an example of the displaydevice of the present invention.

The display device 2 comprises a display panel 50 and an adhesivelayer-equipped transparent surface material 1 bonded to the displaypanel 50 so that the adhesive layer 14 is in contact with the displaypanel 50.

The display device 2 has a protective plate 10, the display panel 50, alayer portion 18 sandwiched by the protective plate 10 and the displaypanel 50, a barrier portion 20 surrounding the periphery of the layerportion 18, and a flexible printed circuit board 60 (FPC) connected tothe display panel 50 and having a driving IC mounted which drives thedisplay panel 50.

Display Panel

The illustrated display panel 50 is an example of a liquid crystal panelhaving a construction wherein a transparent substrate 52 provided with acolor filter and a transparent substrate 54 provided with TFT (a thinfilm transistor) are bonded via a liquid crystal layer 56, and thisassembly is sandwiched between a pair of polarizing plates 58, but thedisplay panel in the present invention is not limited to the illustratedone.

The display panel is one wherein a display material of which the opticalstate changes by an external electrical signal, is sandwiched between apair of electrodes, of which at least one is a transparent electrode.Depending upon the type of the display material, it may, for example, bea liquid crystal panel, an EL panel, a plasma panel, an electron inktype panel or the like. Further, the display panel has a structurewherein a pair of surface materials, of which at least one is atransparent substrate, are bonded to each other, and is disposed so thatthe transparent substrate side is in contact with the layer portion. Atthat time, in some display panels, an optical film such as a polarizingplate or retardation film may be provided on the outermost layer side ofthe transparent substrate in contact with the layer portion. In such acase, the layer portion serves to bond the protective plate and theoptical film on the display panel.

To the bonding surface of the display panel to be bonded to the layerportion, surface treatment may be applied to improve the interfacialbond strength with the barrier portion. Such surface treatment may beonly along the peripheral portion or may be over the entire surface ofthe surface material. The surface treatment method may, for example, bea method of treating with a low temperature-processable bonding primer.

The thickness of the display panel is usually from 0.4 to 4 mm in thecase of a liquid crystal panel to be driven by TFT, or usually from 0.2to 3 mm in the case of an EL panel.

Shape

The shape of the display device is usually rectangular.

The size of the display device is suitably at least 0.5 m×0.4 m,particularly preferably at least 0.7 m×0.4 m in the case of a televisionreceiver using a liquid crystal panel, since the process of the presentinvention is particularly suitable for the production of a displaydevice having a relatively large area. The upper limit for the size ofthe display device is determined by the size of the display panel inmany cases. Further, if the display device is too large, the handling ine.g. installation tends to be difficult. From such restrictions, theupper limit for the size of the display device is usually about 2.5m×1.5 m.

The sizes of the protective plate and the display panel may besubstantially equal, but from the relation with another casing toaccommodate the display device, the protective plate is slightly largerthan the display panel in many cases. Inversely, however, depending uponthe structure of another casing, the protective plate may be made to beslightly smaller than the display panel.

Advantageous Effects

In the above-described display device of the present invention, theadhesive layer-equipped transparent surface material of the presentinvention is bonded to a display panel so that the adhesive layer is incontact with the display panel, whereby formation of voids at theinterface between the display panel and the adhesive layer issufficiently prevented.

The transparent surface material and the display panel are installedwithout via an air layer, whereby reflection of exterior light at an airinterface can be prevented, such being particularly effective in theimprovement of the display contrast when the display screen is viewedfrom an inclined angle.

In the present invention, a cured resin is used as the adhesive layer inthe bonding of the adhesive layer-equipped transparent surface materialand the display panel, whereby a shrinkage stress of the resinaccompanying curing will not be formed, which is likely to be formed bycuring after sandwiching an uncured curable compound or a semi-curedresin film between a transparent surface material and a display panel.Further, the shear modulus value of the layer portion of the adhesivelayer is low, whereby a pressure to be formed at the time of bondingwith the display panel is less likely to remain in the adhesive layer.Therefore, in a case where the display panel is a liquid crystal panel,an adverse effect to the liquid crystal alignment due to such a residualstress is prevented, and a good display quality can be obtained.

Particularly, in the case of a liquid crystal display panel of IPS (inplane switching) system, a display irregularity is likely to occur dueto a stress exerted to the display panel, and the effect by applicationof the present invention is particularly large, and it is possible tosufficiently prevent a change in color from an inclined angle.

<Process for Producing Display Device>

The process for producing a display device of the present invention is aprocess wherein after removing the protective film from the adhesivelayer-equipped transparent surface material of the present invention,the display panel and the adhesive layer-equipped transparent surfacematerial of the present invention are laminated and bonded in a reducedpressure atmosphere of at most 100 Pa so that the adhesive layer is incontact with the display panel.

In order to facilitate the removal of the protective film, the adhesivelayer may be cooled. By cooling the adhesive layer, deformation of theadhesive layer is prevented at the time of removing the protective film,and it is possible to increase the uniformity in thickness of theadhesive layer after removing the protective film and to preventformation of voids at the time of bonding to the display panel.

The temperature for cooling the adhesive layer varies depending upon theglass transition temperature of the resin to be used as the adhesivelayer, but when the glass transition temperature is taken as atemperature showing the maximum value of loss elastic modulus in themeasurement of the shear modulus of elasticity, it is preferably at mostthe temperature higher by about 40° C. than the glass transitiontemperature. The lower limit temperature is not particularly limited,but it is usually at least −30° C., since depending upon the resin to beused for the protective film, the film tends to be brittle at a lowtemperature, and the film is likely to rupture at the time of removal.

The reduced pressure atmosphere at the time of bonding is at most 100Pa, preferably from 1 to 100 Pa, more preferably from 5 to 50 Pa.

The period of time from the time when the display panel and the adhesivelayer-equipped transparent surface material are laminated to the releaseof the reduced pressure atmosphere may be as long as at least a fewhours, but from the viewpoint of the production efficiency, it ispreferably within one hour, more preferably within one minute.

After bonding the display panel and the adhesive layer-equippedtransparent surface material, an incompletely cured adhesive layer maybe again irradiated with light or heated to accelerate the curing of theadhesive layer or to stabilize the cured state of the adhesive layer.

Advantageous Effects

In the above-described process for producing a display device of thepresent invention, the adhesive layer-equipped transparent surfacematerial of the present invention is used wherein an adhesive layer ispreliminarily formed on at least one surface of the transparent surfacematerial, whereby the step of bonding it to the display panel may beonly once, and bonding to the display panel is simple.

Further, the display panel and the adhesive layer-equipped transparentsurface material of the present invention are laminated and bonded in areduced pressure atmosphere of at most 100 Pa so that the adhesive layeris in contact with the display panel, whereby voids are less likely toremain at the interface between the display panel and the adhesivelayer.

Especially, as the layer portion of the adhesive layer is surrounded bythe barrier portion, the thickness of the layer portion can easily bemade uniform, and accordingly, voids are less likely to be formed at theinterface between the display panel and the adhesive layer. Further, theshear modulus of the layer portion is within a specific range, wherebywhen the display panel and the adhesive layer-equipped transparentsurface material are bonded in a reduced pressure atmosphere and thenreturned to an atmospheric pressure atmosphere, voids will readilydisappear and are less likely to remain.

Further, in the adhesive layer-equipped transparent surface material ofthe present invention, a relatively thick adhesive layer is formed whilemaintaining the uniformity in thickness on the surface of thetransparent surface material having a large area, whereby it is possibleto sufficiently prevent formation of voids even in bonding of theadhesive layer-equipped transparent surface material and the displaypanel having a large area which is likely to be deformed.

EXAMPLES

Now, practical Examples will be shown to confirm the effectiveness ofthe present invention, but it should be understood that the presentinvention is by no means restricted to such Examples.

(Number Average Molecular Weight)

The number average molecular weight of an oligomer was obtained as anumber average molecular weight as calculated as polystyrene by using aGPC (gel permeation chromatography) measuring apparatus (HLC-8020,manufactured by TOSOH CORPORATION).

Viscosity

The viscosity of a photocurable resin composition was measured by anE-model viscometer (RE-85U, manufactured by TOKI SANGYO CO., LTD.)

Haze Value

The haze value was obtained by measurement in accordance with ASTM D1003by using Haze-Gard II, manufactured by Toyo Seiki Seisaku-Sho, Ltd.

Shear Modulus

To determine the shear modulus of the layer portion of the adhesivelayer after curing, using a rheometer (modular rheometer PhysicaMCR-301, manufactured by Anton Paar), a space between a measuringspindle and a light-transmitting plate is adjusted to be the same as thethickness of the layer portion, and the uncured first composition isdisposed in the space, and while irradiating the uncured firstcomposition with light required for curing at 35° C., the shear modulusduring the curing process was measured, and the shear modulus of thelayer portion under the curing condition at the time of forming thelayer portion 18, was measured.

In the following Examples, as the transparent surface material, thesupporting surface material, other surface materials such as a displaypanel, etc. and the barrier portion-forming photocurable resincomposition, the following ones were used, respectively.

Examples 1 to 20 Transparent Surface Material

Along the peripheral portion of one surface of soda lime glass having alength of 100 mm, a width of 100 mm and a thickness of 3 mm, alight-shielding printed portion was formed in a frame-form by ceramicprinting containing a black pigment, so that a light-transmittingportion would have a length of 68 mm and a width of 68 mm. Then, overthe entire surface of the back side of the light-shielding printedportion, an antireflection film (ReaLook X401, manufactured by NOFCorporation) was bonded in such a state that a protective film isattached thereto, to prepare a protective plate A.

Supporting Surface Material

On one side of a transparent plate made of soda lime glass having alength of 100 mm, a width of 100 mm and a thickness of 3 mm, aprotective film (Puretect VLH-9, manufactured by Tohcello Co., Ltd.)having a length of 130 mm, a width of 130 mm and a thickness of 0.075 mmwas bonded so that the adhesive surface of the protective film was incontact with the glass, by means of a rubber roll, to prepare asupporting surface material B having the protective film bonded thereto.

Other Surface Materials Such as Display Panel, etc.

As another surface material such as a display panel to be bonded to theprotective plate A via the adhesive layer, a surface material G having apolarizing film provided over one surface of soda lime glass having alength of 90 mm, a width of 90 mm and a thickness of 2 mm, was used. Theprotective plate A was bonded to the surface provided with thepolarizing film. The surface material G is one simulating a liquidcrystal display panel having substantially the same shape.

Barrier Portion-Forming Photocurable Resin Composition

A bifunctional polypropylene glycol having molecular terminals modifiedby ethylene oxide (number average molecular weight calculated by thehydroxy value: 4,000) and hexamethylene diisocyanate were mixed in amolar ratio of 6:7, then diluted with isobornyl acrylate (IBXA,manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.) and then reactedat 70° C. in the presence of a catalyst of a tin compound to obtain aprepolymer, and to this prepolymer, 2-hydroxyethyl acrylate was added ina molar ratio of substantially 1:2, and reacted at 70° C. to obtain asolution of a urethane acrylate oligomer (hereinafter referred to asUC-1) diluted with 30 mass % of isobornyl acrylate. The number ofcurable groups in UC-1 was 2, and the number average molecular weightwas about 55,000. The viscosity at 60° C. of the UC-1 solution was about580 Pa·s.

90 parts by mass of the UC-1 solution and 10 parts by mass of2-hydroxybutyl methacrylate (Light Ester HOB, manufactured by KyoeishaChemical Co., Ltd.) were uniformly mixed to obtain a mixture. 100 partsby mass of such a mixture, 0.9 part by mass of1-hydroxy-cyclohexyl-phenyl-ketone (photopolymerization initiator,IRGACURE 184, manufactured by Ciba Specialty Chemicals), 0.1 part bymass of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide(photopolymerization initiator, IRGACURE 819, manufactured by CibaSpecialty Chemicals) and 0.04 part by mass of2,5-di-tert-butylhydroquinone (polymerization inhibitor, manufactured byTokyo Chemical Industry Co., Ltd.) were uniformly mixed to obtain abarrier portion-forming photocurable resin composition C.

The barrier portion-forming photocurable resin composition C was set ina pressure reducing device, as it was put in a container in an openstate, and the inside of the pressure reducing device was evacuated toabout 20 Pa and maintained for 10 minutes to carry out degassingtreatment. The viscosity at 25° C. of the barrier portion-formingphotocurable resin composition C was measured and found to be about1,470 Pa·s.

Examples 1 to 7 Layer Portion-Forming Photocurable Resin Composition

A bifunctional polypropylene glycol having molecular terminals modifiedwith ethylene oxide (number average molecular weight calculated from thehydroxy value: 4,000) and isophorone diisocyanate were mixed in a molarratio of 4:5 and reacted at 70° C. in the presence of a catalyst of atin compound to obtain a prepolymer, and to such a prepolymer,2-hydroxyethyl acrylate was added in a molar ratio of substantially 1:2and reacted at 70° C. to obtain a urethane acrylate oligomer(hereinafter referred to as UA-1). The number of curable groups in UA-1was 2, the number average molecular weight was about 24,000, and theviscosity at 25° C. was about 830 Pa·s.

40 parts by mass of UA-1, 30 parts by mass of 2-hydroxybutylmethacrylate (Light Ester HOB, manufactured by Kyoeisha Chemical Co.,Ltd.) and 30 parts by mass of n-dodecyl methacrylate were uniformlymixed, and to 100 parts by mass of such a mixture, 0.5 part by mass ofbis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (photopolymerizationinitiator, IRGACURE 819, manufactured by Ciba Specialty Chemicals) and0.01 part by mass of 2,5-di-tert-butylhydroquinone (polymerizationinhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) wereuniformly dissolved to obtain a composition PD.

Then, in the proportions (unit: parts by mass) as shown in Table 1, thecomposition PD and a non-curable oligomer (d1) were uniformly dissolvedto obtain a layer portion-forming photocurable resin composition D.

As the non-curable oligomer (d1), the same bifunctional polypropyleneglycol having molecular terminals modified with ethylene oxide (numberaverage molecular weight calculated from the hydroxy value: 4,000) asused in the synthesis of UA-1, was used.

In the Table, the unit of the amount of the non-curable oligomer (d1) isthe proportion (mass %) when the entirety of the layer portion-formingphotocurable resin composition D is 100 mass % (the same applieshereinafter). For example, in the case of Example 2, 80 parts by mass ofthe composition PD and 20 parts by mass of the non-curable oligomer (d1)were mixed to prepare a layer portion-forming photocurable resincomposition D.

The layer portion-forming photocurable resin composition D was set in apressure reducing device as it was put in a container in an open state,and inside of the pressure reducing device was evacuated to about 20 Paand maintained for 10 minutes to carry out degassing treatment. Theviscosity (unit: Pa·s) at 25° C. of the layer portion-formingphotocurable resin composition D was measured, and the result is shownin Table 1.

Step (a)

Over the entire periphery at a position of about 5 mm from the inneredge of the light-shielding printed portion of the protective plate A,the barrier portion-forming photocurable resin composition C was appliedby a dispenser so that the width would be about 0.7 mm and the appliedthickness would be about 0.6 mm, to form an uncured barrier portion.

Then, ultraviolet light and visible light of at most 450 nm from achemical lamp (FL15BL manufactured by NEC Corporation, peak wavelength:365 nm, irradiation intensity: 2 mW/cm²) were uniformly applied for 30seconds to the uncured barrier portion formed on the protective plate A.The viscosity of the uncured barrier portion was thereby increased.

Step (b)

To a region inside of the barrier portion formed on the protective plateA, the layer portion-forming photocurable resin composition D wassupplied at plural portions so that the total mass would be 2.4 g, bymeans of a dispenser.

During the period for supplying the layer portion-forming photocurableresin composition D, the shape of the uncured barrier portion wasmaintained.

Step (c)

On a lower platen in a pressure reducing device wherein a lifting andlowering device comprising a pair of platens was installed, theprotective plate A was flatly placed so that the surface of the layerportion-forming photocurable resin composition D faces upward.

By means of electrostatic chucks, the supporting surface material Bhaving the protective film bonded thereto was held by the lower surfaceof the upper platen of the lifting and lowering device in the pressurereducing device, so that the distance from the protective plate B wouldbe 10 mm in a vertical direction.

The pressure reducing device was made to be in a sealed state andevacuated until the pressure in the pressure reducing device becameabout 40 Pa. By the lifting and lowering device in the pressure reducingdevice, the upper and lower platens were brought to be close to eachother, and the protective plate A and the supporting surface material Bhaving the protective film bonded thereto, were pressed under a pressureof 2 kPa via the layer portion-forming photocurable resin composition Dand maintained for 10 seconds. The electrostatic chucks were switchedoff, and the supporting surface material was released from the upperplaten, and in about 15 seconds, inside of the pressure releasing devicewas returned to an atmospheric pressure atmosphere to obtain a laminateE wherein an uncured layer portion made of the layer portion-formingphotocurable resin composition D was sealed by the protective plate A,the protective film and the uncured barrier portion.

In the laminate E, the shape of the uncured barrier portion wasmaintained to be substantially the same as the initial state.

Step (d)

To the uncured barrier portion and the uncured layer portion of thelaminate E, from the supporting surface material side, ultraviolet lightand visible light of at most 450 nm from a chemical lamp (FL15BL,manufactured by NEC Corporation, peak wavelength: 365 nm, irradiationintensity: 2 mW/cm²) were uniformly applied for 10 minutes to cure theuncured barrier portion and the uncured layer portion to form anadhesive layer.

The irradiation intensity was measured by means of an illuminometer(ultraviolet intensity meter Unimeter UIT-101, manufactured by USHIOINC.)

A step of removing voids as required at the time of the production by aconventional injection method, is not required. Nevertheless, in each ofExamples 1 to 7, no defects such as voids, etc. remaining in theadhesive layer were observed. Further, defects such as leakage, etc. ofthe layer portion-forming photocurable resin composition from thebarrier portion, were also not observed. The thickness of the layerportion after curing was 0.4 mm and was substantially uniform.

Step (e)

The supporting surface material was removed from the protective film toobtain an adhesive layer-equipped transparent surface material F havingthe protective film bonded thereto.

The shear modulus of the layer portion of the adhesive layer wasmeasured, and the results are shown in Table 1. In Example 7, the curingof the adhesive layer was inadequate, and no measurement of the shearmodulus was carried out.

Lamination with Another Surface Material

After removing the supporting surface material B from the protectivefilm, the assembly was left to stand for 24 hours. Then, the protectivefilm was removed from the adhesive layer on the transparent surfacematerial F, and the adhesive layer-equipped transparent surface materialF having the protective film removed, was flatly placed on the lowerplaten in a pressure reducing device wherein a lifting and loweringdevice comprising a pair of platens was installed, so that the surfaceof the adhesive layer faced upward.

By means of electrostatic chucks, a surface material G was held by thelower surface of the upper platen in the lifting and lowering device inthe pressure reducing device, so that the distance from the adhesivelayer-equipped transparent surface material F became 10 mm.

The pressure reducing device was made to be in a sealed state andevacuated until the pressure in the pressure reducing device becameabout 30 Pa. By the lifting and lowering device in the pressure reducingdevice, the upper and lower platens were brought to be close to eachother, and the display panel G and the adhesive layer-equippedtransparent surface material F were pressed under a pressure of 2 kPavia the adhesive layer and held for 10 seconds. The electrostatic chuckswere switched off, and the surface material G was removed from the upperplaten, and in about 20 seconds, inside of the pressure reducing devicewas returned to an atmospheric pressure to obtain a laminate product H.

Remaining of voids at the time of laminating the adhesive,layer-equipped transparent surface material F and the surface material Gwas observed at points of time of being left to stand still for 20minutes, 1 hour, 3 hours and 24 hours from immediately after theproduction of the laminate product H, and the results are shown in Table1 wherein a case where no remaining voids were observed, is identifiedby O, and a case where remaining voids were observed, is identified by×.

As shown by the results in Table 1, in Example 1 wherein the non-curableoligomer d1 was not contained, and in Example 2 wherein the content ofd1 was 20 mass %, even after being left to stand for 24 hours, voids atthe time of lamination still remained, and the quality of the laminateproduct H was also not desirable. On the other hand, in Examples 3 to 6wherein the non-curable oligomer d1 was contained from 40 to 70 mass %,voids disappeared within 3 hours in each case, and particularly inExamples 5 and 6, voids disappeared in only 20 minutes, and theproductivity was high and good.

In Example 7 wherein the non-curable oligomer d1 was contained in 80mass %, the shear modulus of the adhesive layer became too small, andthe adhesive layer was substantially deformed at the time of removingthe protective film from the transparent surface material F, wherebylamination with the surface material G was not possible.

With respect to Example 5, after being left in an environment at 60° C.with a relative humidity of 90% for 500 hours, the laminate product wasobserved, whereby no formation of voids was observed, and there was nochange from the initial state.

Example 8

Laminate product H-a was obtained in the same manner as in Example 5except that instead of the non-curable oligomer d1, a bifunctionalpolypropylene glycol (number average molecular weight calculated fromthe hydroxy value: 2,000) was used as the non-curable oligomer d2. Inthe same manner as in Examples 1 to 7, remaining of voids at the time oflamination for laminate product H-a was evaluated, and the result isshown in Table 1. Voids disappeared in 20 minutes, and the productivitywas high and good.

Example 9

40 parts by mass of UA-1, 40 parts by mass of 2-hydroxybutylmethacrylate (Light Ester HOB, manufactured by Kyoeisha Chemical Co.,Ltd.) and 20 parts by mass of n-dodecyl methacrylate were uniformlymixed, and to 100 parts by mass of such a mixture, 0.5 part by mass ofbis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (photopolymerizationinitiator, IRGACURE 819, manufactured by Ciba Specialty Chemicals) and0.01 part by mass of 2,5-di-tert-butyl hydroquinone (polymerizationinhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) wereuniformly dissolved to obtain a composition PD-a.

A laminate product H-b was obtained in the same manner as in Example 5except that PD-a was used instead of the composition PD. In the samemanner as in Examples 1 to 8, remaining of voids at the time oflamination for laminate production H-b was evaluated, and the result isshown in Table 1. Voids disappeared in 3 hours.

Example 10

40 parts by mass of UA-1, 20 parts by mass of 2-hydroxybutylmethacrylate (Light Ester HOB, manufactured by Kyoeisha Chemical Co.,Ltd.) and 40 parts by mass of n-dodecyl methacrylate were uniformlymixed, and to 100 parts by mass of this mixture, 0.5 part by mass ofbis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (photopolymerizationinitiator, IRGACURE 819, manufactured by Ciba Specialty Chemicals) and0.01 part by mass of 2,5-di-tert-butylhydroquinone (polymerizationinhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) wereuniformly dissolved to obtain a composition PD-b.

A laminate product H-c was obtained in the same manner as in Example 4except that the composition PD-b was used instead of the composition PDused in Example 3. In the same manner as in Examples 1 to 9, remainingof voids at the time of lamination for the laminate product H-c wasevaluated, and the result is shown in Table 1. Voids disappeared in 20minutes, and the productivity was high and good.

Example 11

A laminate product H-d was obtained in the same manner as in Example 3except that the composition PD used in Example 3 was changed to thecomposition PD-b used in Example 10, and further, instead of thenon-curable oligomer d1 used in Example 3, a trifunctional polypropyleneglycol having molecular terminals modified with ethylene oxide (numberaverage molecular weight calculated from the hydroxy value: 10,000) wasused as a non-curable oligomer d3. In the same manner as in Examples 1to 10, remaining of voids at the time of lamination for the laminateproduct H-d was evaluated, and the result is shown in Table 1. Voidsdisappeared in 20 minutes, and the productivity was high and good.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Layer Compositions CurableUrethane 40 40 40 40 40 40 portion- PD composition acrylate forming PD-aoligomer curable PD-b UA-1 resin (parts by 2- 30 30 30 30 30 30composition D mass) hydroxybutyl methacrylate n-dodecyl 30 30 30 30 3030 methacrylate Photopolymerization 0.5 0.5 0.5 0.5 0.5 0.5 initiatorPolymerization 0.01 0.01 0.01 0.01 0.01 0.01 inhibitor Non-curableoligomer d1 (mass % 0 20 40 50 60 70 in the entire composition D)Non-curable oligomer d2 (mass % 0 0 0 0 0 0 in the entire composition D)Non-curable oligomer d3 (mass % 0 0 0 0 0 0 in the entire composition D)Viscosity (Pa · s) 2.2 1.9 1.6 1.5 1.3 1.3 Layer portion of Shearmodulus (kPa) 300 120 30 14 4 0.8 adhesive layer Evaluation of Voidsdisappeared in X X X X ◯ ◯ laminate product 20 minutes (time requiredfor Voids disappeared in X X X ◯ — — disappearance of 1 hour voids afterVoids disappeared in X X ◯ — — — lamination) 3 hours Voids disappearedin X X — — — — 24 hours Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 LayerCompositions Curable Urethane 40 40 40 40 40 portion- PD compositionacrylate forming PD-a oligomer curable PD-b UA-1 resin (parts by 2- 3030 40 20 20 composition D mass) hydroxybutyl methacrylate n-dodecyl 3030 20 40 40 methacrylate Photopolymerization 0.5 0.5 0.5 0.5 0.5initiator Polymerization 0.01 0.01 0.01 0.01 0.01 inhibitor Non-curableoligomer d1 (mass % 80 0 60 50 0 in the entire composition D)Non-curable oligomer d2 (mass % 0 60 0 0 0 in the entire composition D)Non-curable oligomer d3 (mass % 0 0 0 0 40 in the entire composition D)Viscosity (Pa · s) 1.2 0.9 1.6 1.5 2.4 Layer portion of Shear modulus(kPa) — 1.4 13 8 11 adhesive layer Evaluation of Voids disappeared in —◯ X ◯ ◯ laminate product 20 minutes (time required for Voids disappearedin — — X — — disappearance of 1 hour voids after Voids disappeared in —— ◯ — — lamination) 3 hours Voids disappeared in — — — — — 24 hours

As shown by the results in Table 1, in Examples 3 to 6 and 8 to 11wherein the shear modulus of the layer portion was within the range ofthe present invention, when the adhesive layer-equipped transparentsurface material was bonded to a surface material in a reduced pressureatmosphere and then returned to an atmospheric pressure atmosphere, theperiod of time until voids formed at the interface between the adhesivelayer and the surface material disappeared, was shortened. Particularlyin Examples 5, 6, 8, 10 and 11, large effects were obtained.

Examples 12 to 18

40 parts by mass of UA-1, 20 parts by mass of 2-hydroxybutylmethacrylate (Light Ester HOB, manufactured by Kyoeisha Chemical Co.,Ltd.) and 40 parts by mass of n-dodecyl methacrylate were uniformlymixed, and to 100 parts by mass of this mixture, 0.3 part by mass ofbis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (photopolymerizationinitiator, IRGACURE 819, manufactured by Ciba Specialty Chemicals), 0.04part by mass of 2,5-di-tert-butylhydroquinone (polymerization inhibitor,manufactured by Tokyo Chemical Industry Co., Ltd.), 0.3 part by mass ofan ultraviolet absorber (TINUVIN 109, manufactured by Ciba SpecialtyChemicals) and 0.5 part by mass of n-dodecylmercaptan (chain extender,THIOKALCOL 20, manufactured by Kao Corporation) were uniformly dissolvedto obtain a composition PD-c.

Then, in the proportions (unit: parts by mass) shown in Table 2, thecomposition PD-c and the non-curable oligomer (d1) were uniformlydissolved to obtain a layer portion-forming photocurable resincomposition D-c.

Examples 19 to 20

40 parts by mass of UA-1, 40 parts by mass of 2-hydroxybutylmethacrylate (Light Ester HOB, manufactured by Kyoeisha Chemical Co.,Ltd.) and 20 parts by mass of n-dodecyl methacrylate were uniformlymixed, and to 100 parts by mass of this mixture, 0.3 part by mass ofbis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (photopolymerizationinitiator, IRGACURE 819, manufactured by Ciba Specialty Chemicals), 0.04part by mass of 2,5-di-tert-butylhydroquinone (polymerization inhibitor,manufactured by Tokyo Chemical Industry Co., Ltd.), 0.3 part by mass ofan ultraviolet absorber (TINUVIN 109, manufactured by Ciba SpecialtyChemicals) and 0.5 part by mass of n-dodecylmercaptan (chain extender,THIOKALCOL 20, manufactured by Kao Corporation) were uniformly dissolvedto obtain a composition PD-d.

Then, in the proportions (unit: parts by mass) shown in Table 2, thecomposition PD-d and the non-curable oligomer (d1) were uniformlydissolved to obtain a layer portion-forming photocurable resincomposition D-d.

Evaluation

A laminate product was produced in the same manner as in Example 1 to 7by using the layer portion-forming photocurable resin composition D-c orD-d, and measurements and evaluation of the respective items werecarried out. The results are shown in Table 2.

In step (b), during the period for supplying the layer portion-formingphotocurable resin composition D-c or D-d, the shape of the barrierportion was maintained. The shape of the uncured barrier portion in thelaminate E in step (c) was maintained to be substantially the same as inthe initial state. In the adhesive layer-equipped transparent surfacematerial F after curing in step (d), defects such as voids, etc.remaining in the adhesive layer were not observed. Further, defects suchas leakage, etc. of the layer portion-forming photocurable resincomposition from the barrier portion were also not observed. Thethickness of the layer portion after curing was about 0.4 mm andsubstantially uniform in each case.

TABLE 2 Ex. 12 Ex. 13 Ex. 14 Ex. 15 Ex. 16 Layer Compositions CurableUrethane 40 40 40 40 40 portion- PD-c composition acrylate oligomerforming PD-d UA-1 curable (parts by 2-hydroxybutyl 20 20 20 20 20 resinmass) methacrylate composition n-dodecyl 40 40 40 40 40 D-c methacrylatePhotopolymerization 0.3 0.3 0.3 0.3 0.3 initiator Polymerizationinhibitor 0.04 0.04 0.04 0.04 0.04 Ultraviolet absorber 0.3 0.3 0.3 0.30.3 Chain extender 0.5 0.5 0.5 0.5 0.5 Non-curable oligomer d1 (mass %in 0 10 20 30 40 the entire composition D-c) Viscosity (Pa · s) 2.0 1.91.9 1.8 1.6 Layer portion of Shear modulus (kPa) 150 75 37 27 9 adhesivelayer Evaluation of laminate Voids disappeared in 20 X X X X ◯ product(time required minutes for disappearance of Voids disappeared in 1 X ◯ ◯◯ — voids after lamination) hour Voids disappeared in 3 X — — — — hoursVoids disappeared in 24 ◯ — — — — hours Ex. 17 Ex. 18 Ex. 19 Ex. 20Layer Compositions Curable Urethane 40 40 40 40 portion- PD-ccomposition acrylate oligomer forming PD-d UA-1 curable (parts by2-hydroxybutyl 20 20 40 40 resin mass) methacrylate compositionn-dodecyl 40 40 20 20 D-c methacrylate Photopolymerization 0.3 0.3 0.30.3 initiator Polymerization inhibitor 0.04 0.04 0.04 0.04 Ultravioletabsorber 0.3 0.3 0.3 0.3 Chain extender 0.5 0.5 0.5 0.5 Non-curableoligomer d1 (mass % in 50 60 60 70 the entire composition D-c) Viscosity(Pa · s) 1.5 1.4 1.5 1.3 Layer portion of Shear modulus (kPa) 2.3 — 61.1 adhesive layer Evaluation of laminate Voids disappeared in 20 ◯ — ◯◯ product (time required minutes for disappearance of Voids disappearedin 1 — — — — voids after lamination) hour Voids disappeared in 3 — — — —hours Voids disappeared in 24 — — — — hours

As shown by the results in Table 2, also in Example 12 wherein thenon-curable oligomer d1 was not contained, remaining of voids at thetime of laminating the adhesive layer-equipped transparent surfacematerial F and the surface material G, was not observed in 24 hours.Whereas, in each of Examples 13 to 17, wherein the shear modulus of thelayer portion was within the range of the present invention, voidsdisappeared in 1 hour, and the productivity was increased and good.

It is thereby evident that when a chain extender is added, the shearmodulus of the layer portion becomes sufficiently low and it is possibleto obtain an effect to shorten the time until voids disappear, even whenthe amount of the non-curable oligomer added, was small.

Further, in Example 18, wherein the non-curable oligomer wasincorporated in a larger amount than in Examples 13 to 17, curing of theadhesive layer was inadequate, and removal of the protective film wasdifficult, and the measurement of the shear modulus was not conducted.Thus, it has been found that in a case where a chain extender is to beadded, the content of the non-curable oligomer should better be lowerthan the case where a chain extender is not added.

Further, as shown in Examples 19 and 20, in a case where a chainextender was added, it was possible to increase the curing property ofthe adhesive layer by incorporating the monomer (B4) having an alkylgroup in an amount larger than the monomer (B3) having a hydroxy group,and even in a case where the content of the non-curable oligomer was ashigh as from 60 to 70 mass %, it was possible to let voids disappear in20 minutes, and the productivity was high and good.

Example 21

A laminate product was obtained in the same manner as in Examples 1 to20 by using only soda lime glass having a length of 100 mm, a width of100 mm and a thickness of 2 mm, as another surface material such as adisplay panel, instead of the surface material G having a polarizingfilm provided on one surface of soda lime glass having a length of 90mm, a width of 90 mm and a thickness of 2 mm, used in Examples 1 to 20.The phase value to incident light from the normal direction of thesurface material of the obtained laminate product was measured at 25° C.and found to be at most 1% in every case.

Example 22 Transparent Surface Material

Along the peripheral portion of one surface of soda lime glass having alength of 510 mm, a width of 330 mm and a thickness of 3 mm, alight-shielding printed portion was formed in a frame-form by ceramicprinting containing a black pigment so that the light transmittingportion would have a length of 476 mm and a width of 298 mm. Then, overthe entire surface of the back side of the light-shielding printedportion, an antireflection film (ReaLook X4001, manufactured by NOFCorporation) was bonded in such a state that a protective film wasattached, to prepare a protective plate A′.

Supporting Surface Material

On one side of soda lime glass having a length of 610 mm, a width of 610mm and a thickness of 3 mm, a protective film having a length of 610 mm,a width of 400 mm and a thickness of 0.075 mm (Puretect VLH-9,manufactured by Tohcello Co., Ltd.) was bonded so that the adhesivesurface of the protective film was in contact with the glass, by meansof a rubber roll, to prepare a supporting surface material B′ having aprotective film bonded thereto.

Another Surface Material Such as Display Panel

A liquid crystal display device was taken out from a commerciallyavailable 22-model liquid crystal monitor (product number: 2209WA,manufactured by DELL). The liquid display device had a display mode ofIPS (in plane switching) type and had a length of 489 mm, a width of 309mm and a thickness of about 2 mm. On both surfaces of the liquid crystalpanel, polarizing plates were bonded, and on one side of the long size,six sheets of driving FPC were bonded, and at the ends of FPC, a printedcircuit board was bonded. The image display region had a length of 474mm and a width of 296 mm. Such a liquid crystal display device wasdesignated as a display panel G′.

Barrier Portion-Forming Photocurable Resin Composition

In the same manner as in Examples 1 to 20, the barrier portion-formingphotocurable resin composition C was used.

Layer Portion-Forming Photocurable Resin Composition

The same layer portion-forming photocurable resin composition D as inExample 5 was used.

Step (a)

Over the entire periphery at a position of about 5 mm from the inneredge of the light-shielding printed portion of the protective plate A′,the barrier portion-forming photocurable resin composition C was appliedby a dispenser so that the width would be about 1 mm and the coatingthickness would be about 0.6 mm to form an uncured barrier portion.

Step (b)

In a region inside of the uncured barrier portion applied to theprotective plate A′, the layer portion-forming photocurable resincomposition D was supplied at plural portions so that the total masswould be 62 g, by means of a dispenser.

During the period for supplying the layer portion-forming photocurableresin composition D, the shape of the uncured barrier portion wasmaintained.

Step (c)

The protective plate A′ was flatly placed on a lower platen in apressure reducing device wherein a lifting and lowering devicecomprising a pair of platens was installed, so that the surface of thelayer portion-forming photocurable resin composition D faced upward. Bymeans of electrostatic chucks, the supporting surface material B′ havinga protective film bonded thereto, was held by the lower surface of theupper platen of the lifting and lowering device in the pressure reducingdevice, so that the distance from the protective plate B′ became 30 mmin a vertical direction.

The pressure reducing device was made in a sealed state and evacuateduntil the pressure inside of the pressure reducing device became about10 Pa. By the lifting and lowering device in the pressure reducingdevice, the upper and lower platens were brought to be close to eachother, and the protective plate A′ and the supporting surface materialB′ having a protective film bonded thereto, were pressed under apressure of 2 kPa via the layer portion-forming photocurable resincomposition D and held for one minute. The electrostatic chucks wereswitched off, and from the upper platen, the supporting surface materialwas released, and in about 15 seconds, the inside of the pressurereducing device was returned to the atmospheric pressure atmosphere, toobtain a laminate E′ wherein an uncured layer portion made of the layerportion-forming photocurable resin composition D was sealed by theprotective plate A, the protective film and the uncured barrier portion.

In the laminate E′, the shape of the uncured barrier portion wasmaintained to be substantially the same as in the initial state.

Step (d)

To the uncured barrier portion and the uncured layer portion of thelaminate E′, from the supporting surface material side, ultravioletlight and visible light of at most 450 nm from a chemical lamp wereuniformly applied to cure the uncured barrier portion and the uncuredlayer portion to form an adhesive layer. A step of removing voids asrequired at the time of the production by a conventional injectionmethod, was not required, and nevertheless, defects such as voids, etc.remaining in the adhesive layer were not observed. Further, defects suchas leakage, etc. of the layer portion-forming photocurable resincomposition from the barrier portion were also not observed. Further,the thickness of the adhesive layer was as thick as desired (about 0.4mm).

Step (e)

The supporting surface material was removed from the protective film toobtain an adhesive layer-equipped transparent surface material F′ havingthe protective film bonded thereto.

After removing the supporting surface material from the protective film,the laminate was left to stand for 24 hours, and then, the protectivefilm was removed from the adhesive layer on the transparent surfacematerial F′.

Production of Display Device

The adhesive layer-equipped transparent surface material F′ having theprotective film removed, was flatly placed on the lower platen in thepressure reducing device wherein a lifting and lowering devicecomprising a pair of platens was installed, so that the surface of theadhesive layer faced upward.

By means of electrostatic chucks, the display panel G′ was held by thelower surface of the upper platen of the lifting and lowering device inthe pressure reducing device, so that the distance from the adhesivelayer-equipped transparent surface material F′ became 30 mm.

The pressure reducing device was made in a sealed state and evacuateduntil the pressure in the pressure reducing device became about 10 Pa.By the lifting and lowering device in the pressure reducing device, theupper and lower platens were brought to be close to each other, and thedisplay panel G′ and the adhesive layer-equipped transparent surfacematerial F′ were pressed under a pressure of 2 kPa via the adhesivelayer and held for one minute. The electrostatic chucks were switchedoff, and from the upper platen, the display panel G′ was released, andin about 20 seconds, inside of the pressure reducing device was returnedto the atmospheric pressure, to obtain a display device H′.

When the display device H′ was observed immediately after laminationwith the adhesive layer-equipped transparent surface material F′, manyfine voids were observed at the interface between the display panel G′and the adhesive layer. The display device H′ was left to stand for 20minutes and then observed again, whereby voids were found alldisappeared, and a display device H′ was obtained wherein the displaypanel G′ and the adhesive layer-equipped transparent surface material F′were bonded via the adhesive layer without any defects.

The display device H′ was returned to the casing for a liquid crystalmonitor from which the liquid crystal panel G′ was taken out, andwirings were connected again, and then the liquid crystal monitor wasset so that the display device H′ became vertical. The monitor was leftto stand still for two days and then switched on and connected to acomputer to display an image, whereby over the entire surface of thedisplay screen, a uniform good display image was obtained, and further,a display contrast was higher than the initial. Even when the imagedisplay screen was pressed strongly with a finger, the image was notdisturbed, and the transparent surface material A′ was found toeffectively protect the display panel G′.

Then, in the same manner, the display device F′ was installed, and onemonth later, the bonded position of the display device was checked,whereby no displacement, etc. were observed, and the display device waswell held to the glass plate.

INDUSTRIAL APPLICABILITY

According to the present invention, bonding of the display panel and thetransparent surface material (the protective plate) is simple, and voidsare less likely to remain at the interface between the display panel andthe adhesive layer, such being suitable for the production of a displaydevice having a large surface area.

REFERENCE SYMBOLS

1: Adhesive layer-equipped transparent surface material

2: Display device

10: Protective plate (transparent surface material)

14: Adhesive layer

16: Protective film

18: Layer portion

20: Barrier portion

22: Uncured barrier portion

24: Region

26: Layer portion-forming photocurable resin composition

36: Supporting surface material

50: Display panel

1-13. (canceled)
 14. A display device comprising: a display panel; andan adhesive layer-equipped transparent surface material, the adhesivelayer-equipped transparent surface material comprising a transparentsurface material and an adhesive layer formed on at least one surface ofthe transparent surface material, and being bonded to the display panelsuch that the adhesive layer is in contact with the display panel,wherein the adhesive layer has a layer portion spreading over the atleast one surface of the transparent surface material, wherein the layerportion has a shear modulus at 35° C. of from 0.5 to 100 kPa, whereinthe layer portion is a cured product of a layer portion-forming curableresin composition which comprises a curable compound (II) and anon-curable oligomer (D), and wherein the curable compound (II) is atleast one curable compound which undergoes a curing reaction at the timeof curing the layer portion-forming curable resin composition, providedthat the at least one curable compound has a hydroxy group which is notreactive at the time of curing the layer portion-forming curable resincomposition.
 15. The display device according to claim 14, wherein thedisplay panel is a liquid crystal display panel of in-plane switchingsystem.
 16. The display device according to claim 14, wherein thecurable compound (II) comprises a monomer which has a curable group anda hydroxy group.
 17. The display device according to claim 16, whereinthe curable compound (II) comprises an oligomer (A′) which has a curablegroup and has a number average molecular weight of from 1,000 to100,000, and a monomer (B′) which has a curable group and has a numberaverage molecular weight of from 125 to 600, and wherein the monomer(B′) comprises a monomer (B3) having a hydroxy group.
 18. The displaydevice according to claim 14, wherein the non-curable oligomer (D) has ahydroxy group, and does not undergo a curing reaction with the curablecompound (II) at the time of curing the layer portion-forming curablecomposition.
 19. The display device according to claim 18, wherein thenon-curable oligomer (D) is a polyoxyalkylene polyol, and the oligomer(A′) is a urethane oligomer synthesized by using a polyoxyalkylenepolyol and a polyisocyanate as raw materials.
 20. The display deviceaccording to claim 17, wherein the oligomer (A′) has an acryloyloxygroup, and at least part of the monomer (B′) has a methacryloyloxygroup.
 21. The display device according to claim 17, wherein the monomer(B3) comprises a hydroxyl methacrylate which has a C₃₋₈ hydroxyalkylgroup having from 1 to 2 hydroxy groups.
 22. The display deviceaccording to claim 17, wherein the monomer (B′) comprises a monomer (B4)which is an alkyl methacrylate having a C₈₋₂₂ alkyl group.
 23. Thedisplay device according to claim 17, wherein the layer portion-formingcurable resin composition does not contain a chain transfer agent, orcomprises a chain transfer agent in an amount of at most 1 part by massper 100 parts by mass of the curable compound (II).
 24. The displaydevice according to claim 14, wherein the layer portion-forming curableresin composition comprises a photo-polymerization initiator (C2), andthe curable compound (II) is a photo-curable compound.
 25. The displaydevice according to claim 14, wherein the transparent surface materialis a protective plate for the display device.